feat(cli): implement exp task status command (#19533)

Closes https://github.com/coder/internal/issues/900

- Implements `coder exp task status`
- Adds `testutil.MustURL` helper

testutil/url.go

@@ -0,0 +1,14 @@
+package testutil
+
+import (
+	"net/url"
+	"testing"
+)
+
+func MustURL(t testing.TB, raw string) *url.URL {
+	u, err := url.Parse(raw)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return u
+}