fix!: Roll back the changes that update of LRO metadata type to googl…

…e.cloud.common.OperationMetadata (#6016)

PiperOrigin-RevId: 520464508
Source-Link: googleapis/googleapis@cf01552
Source-Link: googleapis/googleapis-gen@5a981d6
Copy-Tag: eyJwIjoiVmlkZW9TdGl0Y2hlci8uT3dsQm90LnlhbWwiLCJoIjoiNWE5ODFkNjIyZDIzN2IwNTQ3NjA4NjQwOGVjNTIzZmY0YjdjMDYwMCJ9

feat: Update LRO metadata type to google.cloud.common.OperationMetadata
PiperOrigin-RevId: 520405218
Source-Link: googleapis/googleapis@4931d1b
Source-Link: googleapis/googleapis-gen@dd1f114
Copy-Tag: eyJwIjoiVmlkZW9TdGl0Y2hlci8uT3dsQm90LnlhbWwiLCJoIjoiZGQxZjExNDg5ZTMyZTE1YmE1YTViMWE3NmUyYjhmNDc0OGM2YzFkOSJ9

feat: Remove default_ad_break_duration from LiveConfig
PiperOrigin-RevId: 520434307
Source-Link: googleapis/googleapis@273994f
Source-Link: googleapis/googleapis-gen@49986a1
Copy-Tag: eyJwIjoiVmlkZW9TdGl0Y2hlci8uT3dsQm90LnlhbWwiLCJoIjoiNDk5ODZhMTJmZWY0ZjBlZDliMjAwMjI4MzQ3ZTNmNWQyODBjYzcyZiJ9