refactor(app): Standardize subdomain detection logic #13708

Job	Run time
Setup PHP Version for Code Coverage	2s
Others (8.3) / Sanity Tests	3m 12s
Others (8.2) / Sanity Tests	4m 25s
Others (8.4) / Sanity Tests	2m 53s
Others (8.5, --ignore-platform-req=php) / Sanity Tests	4m 46s
SeparateProcess	0s
DatabaseLive	0s
CacheLive	0s
Upload coverage results to Coveralls	0s
	15m 18s

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