feat: add JSON CLI fallback for PET server failures #2302

Job	Run time
Lint	22s
TypeScript Unit Tests (windows-latest)	51s
TypeScript Unit Tests (ubuntu-latest)	24s
Create VSIX	32s
Smoke Tests	0s
Integration Tests (Multi-Root)	-1s
Integration Tests	-1s
E2E Tests	-1s
	2m 6s

Provide feedback