Skip duplicated keys validation due to issue with en.lproj/

Parsing the `en.lproj/Localizable.strings` file when looking for
duplicated keys raises an error.

We haven't been able to identify the error's source, but it could be an
UTF-encoding related issue.

The new localization tooling, 62d1c5e
(#6936), ensures localization files are always UTF-8. I run the linting
on the `en.lproj/Localizable.strings` that the new tooling would
generate on `trunk` and didn't experience the crash.

Side note: The new tooling was introduce after the 9.3 code freeze, so
it's available on `trunk` but hasn't run to generate a new `.strings`
file there yet.

Author: mokagio

fastlane/Fastfile

@@ -917,7 +917,11 @@ platform :ios do
 
   desc 'Lint the `.strings` files'
   lane :lint_localizations do
-    ios_lint_localizations(input_dir: RESOURCES_FOLDER, allow_retry: true)
+    ios_lint_localizations(
+      input_dir: RESOURCES_FOLDER,
+      allow_retry: true,
+      check_duplicate_keys: false # skip for 9.3, which has an issue in the en file
+    )
   end
 
   def write_file(path, contents)