Enable StrictMode in the sample and fix violation in the SDK

[gpunto]

Goal

Enable StrictMode, check violations and fix them.

Implementation

• Enable StrictMode in the sample
• Add suspend + withContext in a couple of functions that are accessing the disk

Testing

Launch the sample and verify that the violation reported for getMimeTypeFromExtension is not logged anymore

Checklist

• Issue linked (if any)
• Tests/docs updated
• I have signed the Stream CLA (required for external contributors)

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled.

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-feeds-android-client	2.39 MB	2.39 MB	0.00 MB	🟢

[sonarqubecloud]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
87.2% Coverage on New Code
0.1% Duplication on New Code

See analysis details on SonarQube Cloud