mgr/dashboard: Remove messages.xlf

Removes the messages.xlf file from the git repository, due to a lot of merge conflicts.
It won't cause any problems, because the file is not important for building or the translation during runtime.

Fixes: https://tracker.ceph.com/issues/38003
Signed-off-by: Sebastian Krah <skrah@suse.com>

.gitignore

@@ -70,3 +70,4 @@ GTAGS
 /src/pybind/mgr/dashboard/frontend/.protractor-report
 /src/pybind/mgr/dashboard/frontend/src/environments/environment.ts
 /src/pybind/mgr/dashboard/frontend/src/environments/environment.prod.ts
+/src/pybind/mgr/dashboard/frontend/src/locale/messages.xlf

src/pybind/mgr/dashboard/HACKING.rst

@@ -333,9 +333,8 @@ parse the TypeScript files.
 When the command ran successfully, it should have created or updated the file
 ``src/locale/messages.xlf``.
 
-To make sure this file is always up to date in master branch, we added a
-validation in ``run-frontend-unittests.sh`` that will fail if it finds
-uncommitted translations.
+The file isn't tracked by git, you can just use it to start with the
+translation offline or add/update the resource files on transifex.
 
 Supported languages
 ~~~~~~~~~~~~~~~~~~~