feat: [Spanner] support excludeTxnFromChangeStreams option

[bshaffer]

Ensures excludeTxnFromChangeStreams is configurable for the following methods, and adds tests:

• Database::runTransaction
• Database::executePartitionedUpdate
• Operation::transaction
• Operation::execute
• Operation::executeUpdate
• Database::batchUpdate

Additionally, ensures excludeTxnFromChangeStreams is NOT configurable for the following methods, and adds tests:

• Transaction::executeUpdate

Database::runTransaction

$database->runTransaction(function (Transaction $t) use ($sql) {
        // Run a query
    }, [
        'transactionOptions' => ['excludeTxnFromChangeStreams' => true]
    ]);

Database::executePartitionedUpdate

$database->executePartitionedUpdate($sql, [
    'transactionOptions' => ['excludeTxnFromChangeStreams' => true]
]);

Operation::transaction

$transaction = $operation->transaction($this->session, [
    'transactionOptions' => ['excludeTxnFromChangeStreams' => true]
]);

Operation::execute

$operation->execute($this->session, $sql, [
   'transaction' => ['begin' => ['excludeTxnFromChangeStreams' => true]]
]);

Operation::executeUpdate

$operation->executeUpdate($this->session, $transaction, $sql, [
   'transaction' => ['begin' => ['excludeTxnFromChangeStreams' => true]]
]);

Database::batchWrite

$database->batchWrite($mutationGroups, [
    'excludeTxnFromChangeStreams' => true
]);

Transaction::executeUpdate

Attempting to call Transaction::executeUpdate with the following options will throw an exception:

// The following throws a `Google\ApiCore\ValidationException`:
$transaction->executeUpdate($sql, [
   'transaction' => ['begin' => ['excludeTxnFromChangeStreams' => true]]
]);