CB-11086 (Android) Fixed a crash when setVolume() is called

[alsorokin]

Platforms affected

Android

What does this PR do?

This is a fix for https://issues.apache.org/jira/browse/CB-11086
It fixes the crash by checking if player is null when trying to set player's volume.

What testing has been done on this change?

Tested on Android emulator 4.4, also checked that added test spec is green on iOS and Windows.

Checklist

• ICLA has been signed and submitted to secretary@apache.org.
• Reported an issue in the JIRA database
• Commit message follows the format: "CB-3232: (android) Fix bug with resolving file paths", where CB-xxxx is the JIRA ID & "android" is the platform affected.
• Added automated test coverage as appropriate for this change.

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[vladimir-kotikov]

LGTM

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Builder Name	Console Output	Test Report	Device Logs
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Windows 10 Store	Link	Link	Link
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iOS	Link	Link	Link
Android	Link	Link	Link