feat: remove LongRunningOperationsManager from Spanner V2 #13811

Job	Run time
Package Tests	13m 5s
Dev Commands Unit Tests	17s
Package Tests (Lowest Dependencies)	13m 2s
PHP 8.0 Unit Test (ubuntu-latest)	3m 22s
PHP 8.1 Unit Test (ubuntu-latest)	4m 28s
PHP 8.2 Unit Test (ubuntu-latest)	4m 12s
PHP 8.3 Unit Test (ubuntu-latest)	4m 5s
PHP 8.0 Unit Test (windows-latest)	7m 44s
PHP 8.1 Unit Test (windows-latest)	9m 40s
PHP 8.2 Unit Test (windows-latest)	9m 29s
PHP 8.3 Unit Test (windows-latest)	9m 52s
PHP 8.0 Unit Test + protobuf extension (ubuntu-latest)	2m 39s
	1h 21m 55s

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