feat(fs-router): change dollar to at in special filenames #5395

Job	Run time
Build Java and TypeScript for other tasks	2m 50s
Test Java	3m 41s
ITs (ubuntu-latest, group-1)	4m 35s
Test TypeScript	2m 2s
ITs (ubuntu-latest, group-2)	6m 5s
Check style	2m 3s
ITs (windows-latest, some)	7m 30s
Gradle tests (ubuntu-latest)	3m 25s
Gradle tests (windows-latest)	8m 36s
Tests Summary	2s
	40m 49s

Provide feedback