Initialize BLE iterator on Matter glib context

[arkq]

Problem

After changes in #25960 BLE iterator in Python binding crashes on VerifyOrDie(g_main_context_get_thread_default() != nullptr) assert.

Changes

Initialize BLE iterator on dedicated Matter glilb context.

Testing

./scripts/build_python.sh --install_wheel build-env -d true
gdb --args python3 .environment/pigweed-venv/bin/chip-repl
> run
In [1]: import chip.ble
In [2]: d = chip.ble.DiscoverSync(timeoutMs=2000)
In [3]: for x in d: print(f"Msg {x}")
[Thread 0x7fffed1fe640 (LWP 2903582) exited]
[New Thread 0x7fffed1fe640 (LWP 2903612)]
[New Thread 0x7fffec8fd640 (LWP 2903614)]

[New Thread 0x7fffd7fff640 (LWP 2903637)]
In [4]:

[arkq]

@tehampson please verify on your side.

[github-actions]

PR #26540: Size comparison from a3b4005 to ed69a46

Decreases (1 build for cc32xx)

platform	target	config	section	a3b4005	ed69a46	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_info	19678442	19678441	-1	-0.0

Full report (1 build for cc32xx)

platform	target	config	section	a3b4005	ed69a46	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	605018	605018	0	0.0
			(read/write)	204164	204164	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197576	197576	0	0.0
			.comment	206	206	0	0.0
			.data	1468	1468	0	0.0
			.debug_abbrev	958615	958615	0	0.0
			.debug_aranges	101232	101232	0	0.0
			.debug_frame	342084	342084	0	0.0
			.debug_info	19678442	19678441	-1	-0.0
			.debug_line	2673606	2673606	0	0.0
			.debug_line_str	513	513	0	0.0
			.debug_loc	33340	33340	0	0.0
			.debug_loclists	1491157	1491157	0	0.0
			.debug_ranges	4984	4984	0	0.0
			.debug_rnglists	94412	94412	0	0.0
			.debug_str	3131974	3131974	0	0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	104322	104322	0	0.0
			.shstrtab	265	265	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	483172	483172	0	0.0
			.symtab	287232	287232	0	0.0
			.text	498572	498572	0	0.0

[tehampson]

Thanks for this. It is working for me!

[andy31415]

fast track: crash hotfix, linux specific.