MM-30988 - Fix racy test ServerSystemdNotification (#16431)

* MM-30988 - Fix racy test ServerSystemdNotification

The translateFunc is a global variable which was unguarded.
So we convert that into an atomic variable to prevent against races.

https://mattermost.atlassian.net/browse/MM-30988

```release-note
NONE
```

* fix tests

* move call upwards

* use race

* after translations init

* guard with a sync.Once

* missed import

* revert race

* update timeout

scripts/test.sh

@@ -16,7 +16,7 @@ echo "Packages to test: $PACKAGES"
 find . -name 'cprofile*.out' -exec sh -c 'rm "{}"' \;
 find . -type d -name data -not -path './vendor/*' -not -path './data' | xargs rm -rf
 
-$GO test $GOFLAGS -run=$TESTS $TESTFLAGS -v -timeout=2000s -covermode=count -coverpkg=$PACKAGES_COMMA -exec $DIR/test-xprog.sh $PACKAGES 2>&1 > >( tee output )
+$GO test $GOFLAGS -run=$TESTS $TESTFLAGS -v -timeout=20m -covermode=count -coverpkg=$PACKAGES_COMMA -exec $DIR/test-xprog.sh $PACKAGES 2>&1 > >( tee output )
 EXIT_STATUS=$?
 
 cat output | $GOBIN/go-junit-report > report.xml