ROU-13124: Fix ChatMessage placeholders cut off in the IDE

[gnbm]

This PR is for ROU-13124: ChatMessage placeholders are cut off in Service Studio.

What was happening

• In Service Studio, the empty Image and Content placeholders of the ChatMessage block collapsed, so their hint text was clipped.

What was done

• Gave the empty Image and Content placeholders a minimum size at design time (-servicestudio-* only, no runtime effect).
• Offset the Image placeholder by the photo gap so the message does not move when an avatar is added (left and right sides).
• Same change ported to both classic-theme/ bundles and logged in the classic README.
• Replaced the deprecated word-break: break-word with overflow-wrap: anywhere (SonarCloud finding).

Test Steps

1. In Service Studio, add an empty ChatMessage (and one with DisplayOnRight) to a screen.
2. Check the placeholder hints are fully visible.
3. Drop an avatar into the Image placeholder and check the message does not move.
4. Repeat with the classic theme.

Screenshots

(add screenshots from Service Studio)

Checklist

• tested locally
• documented the code
• clean all warnings and errors of eslint
• requires changes in OutSystems (if so, provide a module with changes)
• requires new sample page in OutSystems (if so, provide a module with changes)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

🖼️ Storybook: Chromatic UI tests result: ✅ Passed

Metric	Value
Visual changes	0
Errors	0
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