[fix][client-cpp] Fix getLastMessageIdAsync returns ResultNotConnected after seek

[RobertIndie]

Fixes #16761

Motivation

When C++ client calls ConsumerImpl::getLastMessageIdAsync, if the connection is not established, the callback will complete with ResultNotConnected.

Modifications

• Wait until the connection is established while getting the last message id.

Verifying this change

Here is the test for the backoff of ConsumerImpl::getLastMessageIdAsync:

Client client(invalid_url);
Reader reader;
client.createReader(topic, MessageId::latest(), {}, reader);
bool t;
reader.hasMessageAvailable(t);

Here is the output log:

2022-08-04 19:10:44.081 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 100 ms
2022-08-04 19:10:44.084 INFO  [0x7000064fa000] ConsumerImpl:224 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0] Created consumer on broker [127.0.0.1:52918 -> 127.0.0.1:6650] 
2022-08-04 19:10:44.268 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 186 ms
2022-08-04 19:10:44.649 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 376 ms
2022-08-04 19:10:45.380 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 728 ms
2022-08-04 19:10:46.985 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 1600 ms
2022-08-04 19:10:49.933 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 2944 ms
2022-08-04 19:10:55.890 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 5952 ms
2022-08-04 19:11:07.925 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 12032 ms
2022-08-04 19:11:14.011 WARN  [0x7000064fa000] ConsumerImpl:1391 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Could not get connection while getLastMessageId -- Will try again in 6082 ms
2022-08-04 19:11:14.011 ERROR [0x7000064fa000] ConsumerImpl:1376 | [persistent://public/default/reader-test-receive-after-seek-1659611443, reader-c868ade2fb, 0]  Client Connection not ready for Consumer

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