nil pointer dereference when switching contexts

[doy-materialize]

Describe the bug
when using :context to switch to certain contexts i have defined, k9s panics with a nil pointer dereference error

To Reproduce
i don't actually know why some contexts work fine and others fail. with the ones that fail, i can successfully use k9s --context to switch to those contexts at startup, so it appears to only be an issue when using :context.

Historical Documents
k9s.log:

�[90m1:53PM�[0m �[32mINF�[0m �[1m🐶 K9s starting up...�[0m
�[90m1:53PM�[0m �[31mERR�[0m �[1mFail to locate metrics-server�[0m �[36merror=�[0m�[31m�[1m"No metrics api group metrics.k8s.io found on cluster"�[0m�[0m
�[90m1:53PM�[0m �[32mINF�[0m �[1m✅ Kubernetes connectivity�[0m
�[90m1:53PM�[0m �[31mERR�[0m �[1mUsing "default" namespace�[0m
�[90m1:53PM�[0m �[31mERR�[0m �[1mBoom! runtime error: invalid memory address or nil pointer dereference�[0m
�[90m1:53PM�[0m �[31mERR�[0m �[1mgoroutine 1 [running]:
runtime/debug.Stack()
	runtime/debug/stack.go:24 +0x5e
github.com/derailed/k9s/cmd.run.func2()
	github.com/derailed/k9s/cmd/root.go:97 +0xb1
panic({0x64269c5c2260?, 0x64269e7c4380?})
	runtime/panic.go:770 +0x132
github.com/derailed/tview.(*Application).Run.func1()
	github.com/derailed/tview@v0.8.3/application.go:243 +0x45
panic({0x64269c5c2260?, 0x64269e7c4380?})
	runtime/panic.go:770 +0x132
github.com/derailed/k9s/internal/config/data.(*Namespace).merge(0xc00132a1e0, 0x0)
	github.com/derailed/k9s/internal/config/data/ns.go:49 +0x9c
github.com/derailed/k9s/internal/config/data.(*Context).merge(...)
	github.com/derailed/k9s/internal/config/data/context.go:59
github.com/derailed/k9s/internal/config/data.(*Config).Merge(0x0?, 0xc00005c540?)
	github.com/derailed/k9s/internal/config/data/config.go:34 +0x33
github.com/derailed/k9s/internal/config/data.(*Dir).Save(0xc000bb7350, {0xc00005c540, 0x67}, 0xc0004a87e0)
	github.com/derailed/k9s/internal/config/data/dir.go:66 +0x5b
github.com/derailed/k9s/internal/config.(*K9s).Save(0xc000d5c780, 0x1)
	github.com/derailed/k9s/internal/config/k9s.go:84 +0x149
github.com/derailed/k9s/internal/config.(*Config).Save(0xc000df31a0, 0x1)
	github.com/derailed/k9s/internal/config/config.go:239 +0x37
github.com/derailed/k9s/internal/view.(*App).switchContext(0xc000880d80, 0xc001679410, 0x1)
	github.com/derailed/k9s/internal/view/app.go:471 +0x4f0
github.com/derailed/k9s/internal/view.useContext(0xc000880d80, {0xc000e8e7a0, 0x1b})
	github.com/derailed/k9s/internal/view/context.go:130 +0x23f
github.com/derailed/k9s/internal/view.(*Context).useCtx(0xc00167d9f0, 0xc000880d80, {0xc001679580?, 0x64269ad91014?}, {{0x64269aea1496, 0x8}, {0x0, 0x0}, {0x0, 0x0}, ...}, ...)
	github.com/derailed/k9s/internal/view/context.go:105 +0xe5
github.com/derailed/k9s/internal/view.(*Browser).enterCmd(0xc000f9d800, 0xc00049de00)
	github.com/derailed/k9s/internal/view/browser.go:374 +0x10c
github.com/derailed/k9s/internal/view.(*Table).keyboard(0xc00175ebc0, 0xc00049de00)
	github.com/derailed/k9s/internal/view/table.go:97 +0x129
github.com/derailed/k9s/internal/view.(*Browser).InputHandler.(*Table).InputHandler.(*Box).WrapInputHandler.func2(0x6426987770a5?, 0xc0019098b0)
	github.com/derailed/tview@v0.8.3/box.go:179 +0x37
github.com/derailed/k9s/internal/view.(*PageStack).InputHandler.(*Pages).InputHandler.func1(0xc00049de00, 0xc0019098b0)
	github.com/derailed/tview@v0.8.3/pages.go:332 +0xa2
github.com/derailed/k9s/internal/view.(*PageStack).InputHandler.(*Pages).InputHandler.(*Box).WrapInputHandler.func2(0xc0016797d0?, 0x6426987770a5?)
	github.com/derailed/tview@v0.8.3/box.go:182 +0x50
github.com/derailed/tview.(*Flex).InputHandler.func1(0xc00049de00, 0xc0019098b0)
	github.com/derailed/tview@v0.8.3/flex.go:261 +0xd7
github.com/derailed/tview.(*Flex).InputHandler.(*Box).WrapInputHandler.func2(0xc0013e7d70?, 0xc000500008?)
	github.com/derailed/tview@v0.8.3/box.go:182 +0x50
github.com/derailed/k9s/internal/ui.(*Pages).InputHandler.(*Pages).InputHandler.func1(0xc00049de00, 0xc0019098b0)
	github.com/derailed/tview@v0.8.3/pages.go:332 +0xa2
github.com/derailed/k9s/internal/ui.(*Pages).InputHandler.(*Pages).InputHandler.(*Box).WrapInputHandler.func2(0xc001679948?, 0xc0016798b0?)
	github.com/derailed/tview@v0.8.3/box.go:182 +0x50
github.com/derailed/tview.(*Application).Run(0xc0006f8460)
	github.com/derailed/tview@v0.8.3/application.go:334 +0x518
github.com/derailed/k9s/internal/view.(*App).Run(0xc000880d80)
	github.com/derailed/k9s/internal/view/app.go:536 +0x8f
github.com/derailed/k9s/cmd.run(0xc000be6800?, {0x64269ae973ec?, 0x4?, 0x64269ae97304?})
	github.com/derailed/k9s/cmd/root.go:115 +0x3a5
github.com/spf13/cobra.(*Command).execute(0x64269e80ccc0, {0xc000132000, 0x0, 0x0})
	github.com/spf13/cobra@v1.8.0/command.go:983 +0xaca
github.com/spf13/cobra.(*Command).ExecuteC(0x64269e80ccc0)
	github.com/spf13/cobra@v1.8.0/command.go:1115 +0x3ff
github.com/spf13/cobra.(*Command).Execute(...)
	github.com/spf13/cobra@v1.8.0/command.go:1039
github.com/derailed/k9s/cmd.Execute()
	github.com/derailed/k9s/cmd/root.go:70 +0x1a
main.main()
	./main.go:32 +0xf
�[0m

Expected behavior
it shouldn't crash

Versions (please complete the following information):

• OS: arch linux
• K9s: 0.32.4
• K8s: 1.27.10