richeditor/media_box: add ErrorMessages and Disabled

[molon]

No description provided.

[deepsource-io]

Here's the code health analysis summary for commits 0c48c53..2a4dc32. View details on DeepSource ↗.

Analysis Summary

Analyzer	Status	Summary	Link
Test coverage	✅ Success		View Check ↗
Go	✅ Success		View Check ↗

Code Coverage Report

Metric	Aggregate	Go
Composite Coverage	39.7% (up 0.1% from main)	39.7% (up 0.1% from main)
Line Coverage	39.7% (up 0.1% from main)	39.7% (up 0.1% from main)

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files with missing lines	Coverage Δ
media/media_box.go	81.30% <100.00%> (+0.20%)	⬆️
richeditor/richeditor.go	84.48% <100.00%> (+6.43%)	⬆️

... and 11 files with indirect coverage changes