Remove duplicate plus sign for phone numbers (#8871)

Fixes #8838 

1. Summary
It seems [this PR](https://github.com/twentyhq/twenty/pull/8614) caused
the issue. We added a plus sign on front-end when the
[callingCode](c735026f6c/packages/twenty-front/src/modules/ui/field/display/components/PhonesDisplay.tsx (L70))
retrieved from back-end already has a plus sign.

2. Solution
@guillim Please let me know if I missed a case where the plus sign is
not there for the `callingCode`. If so, I think we should check whether
or not `callingCode` has a leading plus sign on front-end before adding
it. For now, I just removed the code that appends a plus sign on
front-end.

3. Screenshots

![localhost_3001_objects_people_view=f4aee583-9d0c-4961-a6e1-fd66bc51dfd5](https://github.com/user-attachments/assets/9fe8b361-47b9-4e3f-82b7-570713cf430c)

---------

Co-authored-by: guillim <guigloo@msn.com>
Co-authored-by: Guillim <guillim@users.noreply.github.com>
Co-authored-by: Weiko <deniaud.corentin@gmail.com>

packages/twenty-front/src/modules/settings/data-model/fields/forms/phones/components/SettingsDataModelFieldPhonesForm.tsx

@@ -37,7 +37,7 @@ export const SettingsDataModelFieldPhonesForm = ({
     .sort((a, b) => a.countryName.localeCompare(b.countryName))
     .map((country) => ({
       label: `${country.countryName} (+${country.callingCode})`,
-      value: `${country.callingCode}`,
+      value: `+${country.callingCode}`,
     }));
   countries.unshift({ label: 'No country', value: '' });
   const defaultDefaultValue = {