docs(firebase_storage): use camel case style for "FlutterFire" in README.md

[nilsreichardt]

Description

To be consistent with other packages, we should write "Flutterfire" in camel case style.

Related Issues

Part of #8745

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Breaking Change

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[nilsreichardt]

Sorry if this is a bit of work to review 22 PRs which also could be only 2 PRs. I thought it's better to split them up to follow conventional commits better and having less changes in a single PR, so someone can better understand the changes when clicking on the linked PR/commit in the changelog: DOCS: use camel case style for "FlutterFire" in REDME.md (#8291) [7b4e06db