[Transaction] internalPinnedExecutor will stuck in acquire semaphore

**Describe the bug**
1. TransactionMetaStoreHandler use a internalPinnedExecutor to execute` new transaction``addPublishPartitionToTxnAsync` and so on.
2. We add a semaphore in TransactionMetaStoreHandler before execute ops.
3. If we new transaction and produce message in callback of new transaction, internalPinnedExecutor will stuck in acquire semaphore, and we also need this internalPinnedExecutor to release semaphore.

**To Reproduce**
Run this test.

>```
> public void testExternalThreadToAcquireSemaphore() throws Exception {
> long st = System.currentTimeMillis();
> String topic = NAMESPACE1 + "/test";
> int numOfTransaction = 1000;
> int transactionTimeoutInSec = 30;
> int numOfMessagesPerTransaction = 20;
>
> Producer producer = pulsarClient.newProducer(Schema.INT64)
> .producerName("transaction-send-test")
> .sendTimeout(0, TimeUnit.SECONDS)
> .topic(topic)
> .enableBatching(false)
> .create();
> CountDownLatch waitSendCompletely = new CountDownLatch(numOfTransaction);
> AtomicBoolean exitByException = new AtomicBoolean(false);
>
> for (int i = 0; i < numOfTransaction; i++) {
> pulsarClient.newTransaction()
> .withTransactionTimeout(transactionTimeoutInSec, TimeUnit.SECONDS)
> .build().whenComplete((transaction, throwable) -> {
> if (throwable != null) {
> log.error("Failed to open transaction", throwable);
> exitByException.set(true);
> } else {
> for (long j = 0; j < numOfMessagesPerTransaction; j++) {
> producer.newMessage(transaction)
> .value(j)
> .sendAsync()
> .whenComplete((messageId, exception) -> {
> if (exception != null) {
> log.error("Failed to send messages", exception);
> exitByException.set(true);
> }
> });
> }
> transaction.commit().thenRun(() -> {
> waitSendCompletely.countDown();
> }).exceptionally(throwable1 -> {
> log.error("Failed to commit the transaction [{}]", transaction, throwable1);
> waitSendCompletely.countDown();
> exitByException.set(true);
> return null;
> });
> }
> });
> }
> new Thread(() -> {
> try {
> Thread.sleep(30000);
> exitByException.set(true);
> waitSendCompletely.countDown();
> } catch (InterruptedException e) {
> e.printStackTrace();
> }
> });
> waitSendCompletely.await();
> assertFalse(exitByException.get());
> log.info("test completely in [{}] secs", (System.currentTimeMillis() - st) / 1000);
> }
>

**Expected behavior**
A clear and concise description of what you expected to happen.

**Screenshots**
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**Additional context**
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Start with TransactionMetaStoreHandler, especially internalPinnedExecutor and the semaphore around transaction operations such as new transaction and addPublishPartitionToTxnAsync. Run testExternalThreadToAcquireSemaphore with the provided transaction and producer workload. Done means the test completes without the executor stalling while acquiring the semaphore, and the final assertion passes.

Written by the indexing model from the issue text.