[UI] Center text in confirmation messages / warnings

### Description
Text is not centered in confirmation message. This might be an issue across all warnings / conf message.

### Test environment
Mobile, iOS

### Preconditions
_Not relevant_

### Test Data
_Not relevant_

### Steps of Reproduction
1. Login
2. Search for an organization, to join them
3. Click on Join org button
4. Fill in joining form
5. Click on Submit button
6. See confirmation message (the issue)

### Expected Result
Text is centered in all confirmation messages / warnings of this type

### Actual Result
Text is left aligned.

### Notes (optional)

### Screenshots (optional)