[Android] Fix Crash when wildcard subscribe

[joonhaengHeo]

If device subscribes to an attribute or event in the WildcardFragment, a crash occurs.
To fix this, I added null check.

[github-actions]

PR #25676: Size comparison from c1810b6 to 3bcc69c

Increases (1 build for cc32xx)

platform	target	config	section	c1810b6	3bcc69c	change	% change
cc32xx	lock	CC3235SF_LAUNCHXL	.debug_info	20245969	20245970	1	0.0

Full report (1 build for cc32xx)

platform	target	config	section	c1810b6	3bcc69c	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	20245969	20245970	1	0.0
			.debug_line	2660979	2660979	0	0.0
			.debug_loc	2804911	2804911	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

[github-actions]

PR #25676: Size comparison from fa2e709 to 2adf43b

Full report (1 build for cc32xx)

platform	target	config	section	fa2e709	2adf43b	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	20245969	20245969	0	0.0
			.debug_line	2660979	2660979	0	0.0
			.debug_loc	2804911	2804911	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