[ObjC] Stop using `xcpretty`.

Something has changed between Xcode and xcpretty such that
we don't get full logs when something fails to know what
file/line is actually failing; so stop using it.

PiperOrigin-RevId: 654830446

.github/workflows/test_objectivec.yml

@@ -57,8 +57,7 @@ jobs:
                 -scheme ProtocolBuffers \
                 -configuration ${{ matrix.xc_config }} \
                 -destination "${{ matrix.destination }}" \
-                test \
-              | xcpretty
+                test
 
       - name: Report ccache stats
         shell: bash