Reuse mq connection when established instead of creating new connections

**Detailed Description**

A clear and concise description of what the bug is.
When app.java creates listener twice then mq fails to initialize the second listener
https://github.com/hashgraph/hedera-hcs-sxc/blob/d2dd8ec94e10213b59f52cb8bcabadd6476c6b55/hcs-lib/src/main/java/com/hedera/hcslib/callback/OnHCSMessageCallback.java#L35

**Actual Behavior**
Steps to reproduce the behavior:
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2. Click on '....'
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**Expected Behavior**

**Environment:**
- Java: [e.g. OpenJDK 11.0.4]
- Node: [e.g. v12.9.1-x86]
- OS: [e.g. Ubuntu 18.04]
- Version: [e.g. 1.0.1]

**Additional Context**
Add any other context about the problem here. Attach any logs here, if applicable.