Disable old fee extensions in non-prod envs (#2933)

The primary annoyance with this is that it means we need (or at least,
should) split all tests that use the fee extension into two separate
tests -- one that simulates non-prod environments, and one that
simulates prod environments. This leads to duplication of many tests but
that's fine since this is theoretically temporary.

prober/src/main/resources/google/registry/monitoring/blackbox/message/delete.xml

@@ -8,4 +8,4 @@
     </delete>
     <clTRID>@@CLTRID@@</clTRID>
   </command>
-</epp>
+</epp>

prober/src/main/resources/google/registry/monitoring/blackbox/message/greeting.xml

@@ -17,4 +17,4 @@
       </statement>
     </dcp>
   </greeting>
-</epp>
+</epp>