fix: do not sign requests that have optional auth #1375

Job	Run time
test / Test (3.0.1)	3m 31s
test / Test (stable)	2m 43s
test / Test (beta)	3m 14s
dart2js_test / Test (3.0.1, chrome)	4m 3s
dart2js_test / Test (3.0.1, firefox)	4m 0s
dart2js_test / Test (stable, chrome)	3m 45s
dart2js_test / Test (stable, firefox)	4m 2s
dart2js_test / Test (beta, chrome)	4m 4s
dart2js_test / Test (beta, firefox)	3m 55s
native_test / Native Test (macos-latest)	4m 33s
native_test / Native Test (windows-latest)	3m 59s
ddc_test / Test (3.0.1, chrome)	3m 16s
ddc_test / Test (3.0.1, firefox)	3m 39s
ddc_test / Test (stable, chrome)	3m 26s
ddc_test / Test (stable, firefox)	3m 47s
ddc_test / Test (beta, chrome)	3m 20s
ddc_test / Test (beta, firefox)	3m 39s
	1h 2m 56s

Provide feedback