Android: on call end the memory claimed by SDK is not deallocated

**Describe the bug**

On call end, the application memory usage is not same as before starting call.

Application memory usage:
Before starting call - 150 mb
On start call - 240 mb
After call end - 182 mb

Tested on `azure-communication-calling-1.0.0-beta.1.aar`

Disposing call agent & call client to cleanup memory.

```
return call.hangUp(HangUpOptions()).thenRun {
callAgent.close()
callClient.close()
call = null
}
```

**To Reproduce**
Steps to reproduce the behaviour:
1. Start call
2. Attach android studio profiler
3. End call
4. Explore memory

**Expected behavior**
After call end, the memory claimed by application may be equal to before call.

**Desktop (please complete the following information):**
- OS: Mac

**Smartphone (please complete the following information):**
- Device: Google Pixel 4
- OS: Android 11
- Version `azure-communication-calling-1.0.0-beta.1.aar`

https://skype.visualstudio.com/SPOOL/_workitems/edit/2464754