Ignores invalid timestamps in requests (use current time)

Fix this issue: https://www.reddit.com/r/navidrome/comments/ql3imf/scrobbling_fails_when_using_substreamer/

utils/request_helpers_test.go

@@ -92,6 +92,13 @@ var _ = Describe("Request Helpers", func() {
 		It("returns all param occurrences as []time.Time", func() {
 			Expect(ParamTimes(r, "t")).To(Equal([]time.Time{d1, d2}))
 		})
+		It("returns current time as default if param is invalid", func() {
+			now := time.Now()
+			r = httptest.NewRequest("GET", "/ping?t=null", nil)
+			times := ParamTimes(r, "t")
+			Expect(times).To(HaveLen(1))
+			Expect(times[0]).To(BeTemporally(">=", now))
+		})
 	})
 
 	Describe("ParamInt", func() {