Update dependency firebase-functions to v5.1.0

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
firebase-functions	5.0.1 -> 5.1.0

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Release Notes

firebase/firebase-functions (firebase-functions)

### [`v5.1.0`](https://togithub.com/firebase/firebase-functions/compare/v5.0.1...6fbadd7ba7435000afa3a1a9732ddaec07898de6) [Compare Source](https://togithub.com/firebase/firebase-functions/compare/v5.0.1...v5.1.0)

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