fix: only add `.nr` files to file manager #4029

Job	Run time
build-acvm-js	2m 28s
build-noirc-abi	2m 37s
build-nargo	2m 27s
build-noir-wasm	2m 34s
ACVM JS (Browser)	1m 15s
ACVM JS (Node.js)	33s
noir_wasm	1m 3s
noir_codegen	56s
Integration Tests (Node)	5m 33s
Noir JS	1m 37s
noirc_abi	39s
noir-js-backend-barretenberg	39s
Integration Tests (Browser)	5m 0s
End	1s
	27m 22s

Provide feedback