**feat**: create `SendGrantValidator` and initial `SendPasswordValidator` for Send access grants
**feat**: add feature flag to toggle Send grant validation logic
**feat**: add Send client to Identity and update `ApiClient` to generic `Client`
**feat**: register Send services in DI pipeline
**feat**: add claims management support to `ProfileService`
**feat**: distinguish between invalid grant and invalid request in `SendAccessGrantValidator`
**fix**: update parsing of `send_id` from request
**fix**: add early return when feature flag is disabled
**fix**: rename and organize Send access scope and grant type
**fix**: dotnet format
**test**: add unit and integration tests for `SendGrantValidator`
**test**: update OpenID configuration and API resource claims
**doc**: move documentation to interfaces and update inline comments
**chore**: add TODO for future support of `CustomGrantTypes`
* Add DynamicClientStore
* Formatting
* Fix Debug assertion
* Make Identity internals visible to its unit tests
* Add installation client provider tests
* Add internal client provider tests
* Add DynamicClientStore tests
* Fix namespaces after merge
* Format
* Add docs and remove TODO comments
* Use preferred prefix for API keys
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Co-authored-by: Jared Snider <116684653+JaredSnider-Bitwarden@users.noreply.github.com>
