Fix isBatchActive of RCTCxxBridge (#22785)

Summary:
Seems we lost handler of `isBatchActive` from [RCTBatchedBridge a86171a](https://github.com/facebook/react-native/blob/a86171a48284c440226a79a26c6d6a4704d401e9/React/Base/RCTBatchedBridge.m) to [RCTCxxBridge 5bc7e39](https://github.com/facebook/react-native/commit/b774820dc29eae5a09e570384636d353afe213c2#diff-a2a67635fffd7b690d14dc17ae563a71).

Changelog:
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[iOS] [fixed] - Fix isBatchActive of RCTCxxBridge
Pull Request resolved: https://github.com/facebook/react-native/pull/22785

Reviewed By: mhorowitz

Differential Revision: D13731897

Pulled By: cpojer

fbshipit-source-id: 8d6b85bcea8fe8997a93b4e1ac8b8007422ca20e