Allow default matrix selection override #5289

Job	Run time
Lint	29s
Get minimum supported rust version	18s
SDK docs	1m 26s
Code Style	49s
SDK Tests (stable, false)	3m 50s
WASM Tests (stable, false)	2m 29s
E2E Tests (stable, false)	1m 55s
SDK Tests (1.76, false)	3m 55s
WASM Tests (1.76, false)	1m 4s
E2E Tests (1.76, false)	2m 10s
SDK Tests (nightly, true)	3m 1s
WASM Tests (nightly, true)	2m 26s
E2E Tests (nightly, true)	1m 7s
	24m 59s

Provide feedback