[QPG] Removal OPENTHREAD_CONFIG_CHILD_SUPERVISION_ENABLE flag

[tima-q]

The OPENTHREAD_CONFIG_CHILD_SUPERVISION_ENABLE has become default in the latest Thread code. Unblocks #25480 Thread version update.

[github-actions]

PR #25518: Size comparison from fc0e4a2 to 5e034f2

Increases (1 build for nrfconnect)

platform	target	config	section	fc0e4a2	5e034f2	change	% change
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	text	808432	808436	4	0.0

Decreases (1 build for nrfconnect)

platform	target	config	section	fc0e4a2	5e034f2	change	% change
nrfconnect	all-clusters-minimal-app	nrf52840dk_nrf52840	text	777580	777576	-4	-0.0

Full report (8 builds for efr32, mbed, nrfconnect)

platform	target	config	section	fc0e4a2	5e034f2	change	% change
efr32	lighting-app	BRD4161A+rs9116	(read/write)	1030964	1030964	0	0.0
			.bss	179284	179284	0	0.0
			.data	2060	2060	0	0.0
			.text	849600	849600	0	0.0
		BRD4187C	(read/write)	1013820	1013820	0	0.0
			.bss	148176	148176	0	0.0
			.data	2696	2696	0	0.0
			.text	838352	838352	0	0.0
	lock-app	BRD4161A+wf200	(read/write)	1056724	1056724	0	0.0
			.bss	150572	150572	0	0.0
			.data	2068	2068	0	0.0
			.text	904064	904064	0	0.0
	window-app	BRD4187C	(read/write)	1130372	1130372	0	0.0
			.bss	132608	132608	0	0.0
			.data	2588	2588	0	0.0
			.text	970580	970580	0	0.0
mbed	lock-app	CY8CPROTO_062_4343W+release	(read only)	6224	6224	0	0.0
			(read/write)	2467600	2467600	0	0.0
			.bss	215804	215804	0	0.0
			.data	5880	5880	0	0.0
			.text	1430244	1430244	0	0.0
nrfconnect	all-clusters-app	nrf52840dk_nrf52840	(read only)	4	4	0	0.0
			(read/write)	1168052	1168052	0	0.0
			bss	143423	143423	0	0.0
			rodata	136352	136352	0	0.0
			text	808432	808436	4	0.0
		nrf7002dk_nrf5340_cpuapp	(read only)	4	4	0	0.0
			(read/write)	1373056	1373056	0	0.0
			bss	105902	105902	0	0.0
			rodata	213740	213740	0	0.0
			text	767920	767920	0	0.0
	all-clusters-minimal-app	nrf52840dk_nrf52840	(read only)	4	4	0	0.0
			(read/write)	1113072	1113072	0	0.0
			bss	142579	142579	0	0.0
			rodata	113196	113196	0	0.0
			text	777580	777576	-4	-0.0