Improve translation debugging logging not work

The debug flag is set as a static variable, it only be reset after
the process restarted. We receive many bugs that the debug flag is
not enabled correctly, it's hard to guide users to do the correct
set up. To improve this, we check isLoggable before logging it. This
should improve the debug process with lab.

Bug: 253558603
Bug: 230018939
Test: adb shell setprop log.tag.UiTranslation DEBUG and start the
chat apps. The debug log can be printed

Change-Id: I5b3cb1c2761641346ac800b1a19fd961f88a1886