Fix video streaming incorrect restart

[joeygrover]

This PR is ready for review.

Risk

This PR makes no API changes.

Testing Plan

• I have verified that I have not introduced new warnings in this PR (or explain why below)
• I have run the unit tests with this PR
• I have tested this PR against Core and verified behavior (if applicable, if not applicable, explain why below).
• I have tested Android

Summary

Added a flag to prevent a listener from being added multiple times and with each time being added, it gets an immediate callback which therefore causes the video stream to stop and restart. This caused issues when the IVI simply displays an alert or dialog over the stream which would move the app to HMI_LIMITED but cause the stream to stop and restart.

Also added a check for null in the remote display class as it was simply just catching the NPE and printing it out in normal logs. It will no longer cause an NPE and exceptions will be logged through the DebugTool instead of Log.

Changelog

Bug Fixes

• Incorrectly restarting stream when moving between HMI states
• Avoidable NPE in the remote display class

CLA

• I have signed the CLA

[codecov]

Codecov Report

Merging #1655 (5868f06) into release/5.1.0_RC (33d2fbb) will increase coverage by 0.01%.
The diff coverage is 8.33%.

@@                  Coverage Diff                   @@
##             release/5.1.0_RC    #1655      +/-   ##
======================================================
+ Coverage               54.01%   54.02%   +0.01%     
- Complexity               5306     5308       +2     
======================================================
  Files                     555      555              
  Lines                   24530    24534       +4     
  Branches                 3093     3095       +2     
======================================================
+ Hits                    13249    13254       +5     
- Misses                  10130    10135       +5     
+ Partials                 1151     1145       -6     

Impacted Files	Coverage Δ	Complexity Δ
...rtdevicelink/streaming/video/SdlRemoteDisplay.java	51.21% <0.00%> (+0.60%)	5.00 <0.00> (ø)
...tdevicelink/managers/video/VideoStreamManager.java	22.40% <25.00%> (+0.06%)	21.00 <0.00> (ø)
...ink/managers/screen/BaseTextAndGraphicManager.java	63.75% <0.00%> (-0.42%)	50.00% <0.00%> (-2.00%)
...managers/screen/TextAndGraphicUpdateOperation.java	72.25% <0.00%> (+1.09%)	121.00% <0.00%> (+4.00%)