Tinted theme: mention suggestion window has white text on light background

[chefranov]

Environment:

• Telegram app version: 12.2
• iOS version: 26.1 / System theme: light
• Theme: tinted

Bug: When mentioning a user in chat, the suggestion window that appears has a light background and white text. This makes the text unreadable because it blends with the background.

Steps to reproduce:

1. Open Telegram app on iOS.
2. Start typing a username to mention someone in chat.
3. Observe the suggestion window for user mentions.

Actual result: Suggestion window shows white text on light background (not readable).

Expected result: Text in the suggestion window should be visible (contrast with background).

Screenshot: