Revert "Update mozrunner from 7.0.0 to 7.0.1" (#10739)

This reverts commit 8b9f853fd06ca887b340e77e342d323c32635a13

See https://github.com/w3c/web-platform-tests/issues/10736
diff --git a/tools/wptrunner/requirements_firefox.txt b/tools/wptrunner/requirements_firefox.txt
index e9c79d0..0eb26e7 100644
--- a/tools/wptrunner/requirements_firefox.txt
+++ b/tools/wptrunner/requirements_firefox.txt
@@ -2,7 +2,7 @@
 mozprofile==1.1.0
 mozprocess == 0.26
 mozcrash == 1.0
-mozrunner==7.0.1
+mozrunner == 7.0.0
 mozleak == 0.1
 mozinstall == 1.15
 mozdownload == 1.23