Add allow_system_index_access to docs tests where necessary

Note: these should be removed and replaced with actual APIs everywhere this is necessary.

x-pack/docs/en/watcher/managing-watches.asciidoc

@@ -28,7 +28,7 @@ For example, the following returns the first 100 watches:
 
 [source,console]
 --------------------------------------------------
-GET .watches/_search
+GET .watches/_search?allow_system_index_access=true
 {
   "size" : 100
 }

x-pack/docs/en/watcher/troubleshooting.asciidoc

@@ -16,7 +16,7 @@ do that by submitting the following request:
 
 [source,console]
 --------------------------------------------------
-GET .watches/_mapping
+GET .watches/_mapping?allow_system_index_access=true
 --------------------------------------------------
 // TEST[setup:my_active_watch]
 
@@ -31,7 +31,7 @@ mappings:
 --
 [source,console]
 --------------------------------------------------
-DELETE .watches
+DELETE .watches?allow_system_index_access=true
 --------------------------------------------------
 // TEST[skip:index deletion]
 --
@@ -62,4 +62,4 @@ Keep in mind that there's no built-in validation of scripts that you add to a
 watch. Buggy or deliberately malicious scripts can negatively impact {watcher}
 performance. For example, if you add multiple watches with buggy script
 conditions in a short period of time, {watcher} might be temporarily unable to
-process watches until the bad watches time out.
+process watches until the bad watches time out.