Use ArraySize where needed in src/app.

[bzbarsky-apple]

Fixes #8372

[github-actions]

PR #25657: Size comparison from bc8c9ec to ab91dcc

Full report (1 build for cc32xx)

platform	target	config	section	bc8c9ec	ab91dcc	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	645097	645097	0	0.0
			(read/write)	203848	203848	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197248	197248	0	0.0
			.comment	194	194	0	0.0
			.data	1480	1480	0	0.0
			.debug_abbrev	930293	930293	0	0.0
			.debug_aranges	87384	87384	0	0.0
			.debug_frame	300248	300248	0	0.0
			.debug_info	20275632	20275632	0	0.0
			.debug_line	2660982	2660982	0	0.0
			.debug_loc	2804957	2804957	0	0.0
			.debug_ranges	283168	283168	0	0.0
			.debug_str	3026158	3026158	0	0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	105993	105993	0	0.0
			.shstrtab	232	232	0	0.0
			.stab	204	204	0	0.0
			.stabstr	441	441	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	379204	379204	0	0.0
			.symtab	256912	256912	0	0.0
			.text	536984	536984	0	0.0

[github-actions]

PR #25657: Size comparison from b02a6ca to 9d31fae

Full report (1 build for cc32xx)

platform	target	config	section	b02a6ca	9d31fae	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL		0	0	0	0.0
			(read only)	645489	645489	0	0.0
			(read/write)	203848	203848	0	0.0
			.ARM.attributes	44	44	0	0.0
			.ARM.exidx	8	8	0	0.0
			.bss	197248	197248	0	0.0
			.comment	194	194	0	0.0
			.data	1480	1480	0	0.0
			.debug_abbrev	930293	930293	0	0.0
			.debug_aranges	87384	87384	0	0.0
			.debug_frame	300248	300248	0	0.0
			.debug_info	20245970	20245970	0	0.0
			.debug_line	2660979	2660979	0	0.0
			.debug_loc	2804893	2804893	0	0.0
			.debug_ranges	283168	283168	0	0.0
			.debug_str	3026947	3026947	0	0.0
			.ramVecs	780	780	0	0.0
			.resetVecs	64	64	0	0.0
			.rodata	106009	106009	0	0.0
			.shstrtab	232	232	0	0.0
			.stab	204	204	0	0.0
			.stabstr	441	441	0	0.0
			.stack	2048	2048	0	0.0
			.strtab	380271	380271	0	0.0
			.symtab	257312	257312	0	0.0
			.text	537360	537360	0	0.0