FLEXIN-737: Update logic for filename truncation

[mdeshpande12]

• Updated definition for Notification interface
• Updated logic for shortening for filename for it to truncate the filename only when filename characters are more than 20 characters
• Moved file related logic to single file.ts utility file.

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[mdeshpande12]

Added following changes:

• Moved file related logic to single file.ts utility file.
• Reverted back the logic from commit a7a2dc127300e8a42f21d967ce55bfaec74212d5; as I noticed issues in parsing of Map DataStructure in localStorage

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud