fix(experimentalIdentityAndAuth): remove extra `$` from `HttpApiKeyAuthSigner` #2344

Job	Run time
Ensure TypeScript is formatted	1m 39s
Java 17 macos-latest	2m 22s
TypeScript Lint	1m 29s
Java 17 ubuntu-latest	2m 23s
Ensure TypeScript packages have changesets	49s
Java 17 windows-latest	3m 39s
TypeScript Test	30m 14s
	42m 35s

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