Fix crash on launch in nightly

The priority field is no longer supported.

This crash was reported in
https://gitlab.com/fdroid/acra-crash-reports/-/issues/173.

In
https://matrix.to/#/!UAdCANfoQdxlMXhNuM:f-droid.org/$RQa00dUdnkUsmz_iCXh-JDjlJDo9ZynoTHazBT7GiUI?via=f-droid.org&via=matrix.org&via=mozilla.org
it was found that the nightly repo was the culprit.

This crash only affected the nightly builds, not the regular builds.

config/nightly-repo/repo.xml

@@ -4,8 +4,6 @@
         <item>13</item>
         <!-- enabled -->
         <item>1</item>
-        <!-- priority -->
-        <item>5</item>
         <!-- push requests -->
         <item>ignore</item>
         <!-- pubkey -->