[symfony/translation] remove fallbacks config

[kbond]

Q	A
License	MIT
Doc issue/PR	n/a

I was a confused why this fallbacks is needed - turns out it isn't, and uses the default_locale if not set. I suggest removing and letting the default_locale be used - this feels like the 90%+ case.

Having multiple fallbacks feels like a pretty advanced case.

This also falls under the recipe simplification initiative.

[github-actions]

Thanks for the PR 😍

How to test these changes in your application

1. Define the SYMFONY_ENDPOINT environment variable:

   # On Unix-like (BSD, Linux and macOS)
   export SYMFONY_ENDPOINT=https://raw.githubusercontent.com/symfony/recipes/flex/pull-1423/index.json
   # On Windows
   SET SYMFONY_ENDPOINT=https://raw.githubusercontent.com/symfony/recipes/flex/pull-1423/index.json

2. Install the package(s) related to this recipe:

   composer req symfony/flex
   composer req 'symfony/translation:^6.3'

3. Don't forget to unset the SYMFONY_ENDPOINT environment variable when done:

   # On Unix-like (BSD, Linux and macOS)
   unset SYMFONY_ENDPOINT
   # On Windows
   SET SYMFONY_ENDPOINT=

Diff between recipe versions

In order to help with the review stage, I'm in charge of computing the diff between the various versions of patched recipes.
I'm going keep this comment up to date with any updates of the attached patch.

symfony/translation

3.3 vs 5.3

diff --git a/symfony/translation/3.3/config/packages/translation.yaml b/symfony/translation/5.3/config/packages/translation.yaml
index 05a2b3d..b3f8f9c 100644
--- a/symfony/translation/3.3/config/packages/translation.yaml
+++ b/symfony/translation/5.3/config/packages/translation.yaml
@@ -4,3 +4,4 @@ framework:
         default_path: '%kernel.project_dir%/translations'
         fallbacks:
             - en
+        providers:

5.3 vs 6.3

diff --git a/symfony/translation/5.3/config/packages/translation.yaml b/symfony/translation/6.3/config/packages/translation.yaml
index b3f8f9c..490bfc2 100644
--- a/symfony/translation/5.3/config/packages/translation.yaml
+++ b/symfony/translation/6.3/config/packages/translation.yaml
@@ -2,6 +2,4 @@ framework:
     default_locale: en
     translator:
         default_path: '%kernel.project_dir%/translations'
-        fallbacks:
-            - en
         providers: