docs: Clarify that IAM RPCs apply to buckets as well as objects

feat!: Removed upload_id from DeleteObjectRequest, and in its place defined separate CancelResumableWriteRequest RPC

feat: Added optional object_size to WriteObjectSpec, as constraint on object being written

docs: Clarified project ID format of various RPCs

docs: Clarified behavior of update_mask in UpdateHmacKeyRequest

docs: Clarified meaning/behavior of fields in HmacKeyMetadata

docs: Clarified cases where update_time is updated in Bucket message

docs: Clarified UpdateHmacKeyRequest.update_mask behavior

docs: Clarified meaning of <projectIdentifier> for several RPCs
PiperOrigin-RevId: 461979598

Source-Link: googleapis/googleapis@2938d54

Source-Link: googleapis/googleapis-gen@b2bc85c
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiYjJiYzg1YzJlMDBiYjNlZjhmNWFhY2NmMzQzYjBkOTQyOGQ0ZGMzZCJ9

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

Allow removal of DeleteObjectRequest.upload_id
Allow addition of WriteObjectSpec.object_size