feat: order by key when printing labels

[phm07]

This PR adds sorting of labels by their keys, which is useful for testing, since iteration order over maps in Go is undefined by default.
It uses the Go 1.23 iteration feature. If we want to use this, we should probably bump the Go version in a separate PR.

[codecov]

Codecov Report

Attention: Patch coverage is 63.15789% with 7 lines in your changes missing coverage. Please review.

Project coverage is 69.98%. Comparing base (d7fd0ca) to head (d3fc1ed).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/cmd/util/util.go	62.50%	2 Missing and 1 partial ⚠️
internal/cmd/loadbalancer/describe.go	0.00%	1 Missing ⚠️
internal/cmd/primaryip/describe.go	0.00%	1 Missing ⚠️
internal/cmd/server/describe.go	0.00%	1 Missing ⚠️
internal/cmd/volume/describe.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #960      +/-   ##
==========================================
- Coverage   70.01%   69.98%   -0.03%     
==========================================
  Files         245      245              
  Lines       10715    10716       +1     
==========================================
- Hits         7502     7500       -2     
- Misses       2537     2539       +2     
- Partials      676      677       +1     

Flag	Coverage Δ
e2e	46.78% <57.89%> (+<0.01%)	⬆️
unit	63.43% <57.89%> (-0.03%)	⬇️

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