submodule: bump third_party/openthread/repo from `025d84b` to `ada03e6` #5319

Job	Run time
Border Router (mDNSResponder)	29m 30s
Border Router (Avahi)	29m 23s
Border Router TREL (mDNSResponder)	29m 22s
Border Router TREL (Avahi)	29m 10s
Border Router MATN (mDNSResponder)	18m 30s
Border Router Internet Access Features (mDNSResponder)	25m 49s
Backbone Router	17m 18s
Border Router TREL with FEATURE_FLAG (avahi)	29m 21s
	3h 28m 23s

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