set the volume to 50% when the app starts

[RickyRiko305]

PR checklist	Status
Is issue created in GitHub?	Yes
Is code analysis task executed and issues resolved in the Java/Kotlin code?	Yes
Is code analysis task executed and issues resolved in the CPP/native code?	NA
Is the version code set in the AndroidManifest.xml or build.gradle file to 1 more than the version which has already been published?	NA
Is code commenting done properly for the changes made?	Yes
Is correct variable naming convention followed?	Yes
Is auto formatting shortcut Ctrl+Alt+Shift+L executed in all files?	Yes
Are the message strings used in the application taken from strings.xml file?	NA
Are the permissions which are not required removed from AndroidManifest.java file?	NA
Is the uses-feature tag used for only must have feature in AndroidManifest.java file?	NA
Are the generated files correctly configured in .gitignore?	NA
Are the release signing configurations removed from the gradle files?	NA
Is commented code removed from all files?	NA
Are updated images compressed (< 100 KB)?	NA
Ensured there are no typos in any string. For example: Variable/method names, hardcoded strings, commit messages, PR titles, issues, code comments?	Yes