Drop isSupported injection, bump rxfire #2123

Job	Run time
Build	3m 19s
Contribute Node 20 (ubuntu-latest)	1m 52s
Contribute Node 20 (macos-latest)	4m 40s
Contribute Node 20 (windows-latest)	6m 41s
Test chrome-headless	3m 42s
Test Node 18 (ubuntu-latest)	3m 15s
Test firefox-headless	1m 41s
Test Node 20 (ubuntu-latest)	21s
Test Node 22 (ubuntu-latest)	3m 9s
Test Node 18 (macos-latest)	3m 31s
Test Node 20 (macos-latest)	31s
Test Node 22 (macos-latest)	3m 14s
Test Node 18 (windows-latest)	4m 12s
Test Node 20 (windows-latest)	4m 46s
Test Node 22 (windows-latest)	3m 59s
Branch protection	1s
Publish (NPM)	0s
	48m 54s

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