Missing ninth digit prefix prevents contact synchronization in Brazil

[o-thiago]

Guidelines

• I have searched searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• This isn't a feature request or a discussion topic

Bug description

Signal fails to synchronize contacts when Brazilian mobile numbers are stored in the phone's address book without the mandatory "9" prefix.

In Brazil, mobile numbers were updated to a 9-digit format: +55 (DD) 9XXXX-XXXX. However, many users have legacy contacts or contacts imported from other apps stored as +55 (DD) XXXX-XXXX (8 digits).

Because Signal requires the 9-digit format to match accounts, these contacts do not appear in the app’s contact list, even if the person has an active Signal account.

This issue is likely present on all Signal versions which didn't account for that, I myself only tested Android though. This issue is a major blocker preventing people on Brazil to migrate over to Signal. They see that their contacts do not appear and they think the app might be broken, but is just the fact that Signal does not handle the phone numbers correctly.

Related: #10854

Screenshots

No response

Device

Samsung Galaxy S23

Android version

16

Signal version

8.4.1

Link to debug log

No response