Rename en_TEST to en_TST

Because it doesn't fit in db field spree_users.local with limit: 6.
We could extend the field but it seemed silly because it's only used in test/dev environments.

.env.development

@@ -8,7 +8,7 @@
 # Locale for translation. Using a locale other than `en` tests the
 # successful fallback to `en`. You will also see up-to-date text used
 # in production
-LOCALE="en_TEST"
+LOCALE="en_TST"
 
 VERBOSE_QUERY_LOGS=true
 

.env.test

@@ -2,7 +2,7 @@
 # Override locally with `.env.test.local`
 
 # Locale for translation.
-LOCALE="en_TEST"
+LOCALE="en_TST"
 
 OFN_REDIS_JOBS_URL="redis://localhost:6379/2"