Docs: Remove note about running watches with elevated privileges

The documentation still mentioned that watches are running with elevated
privileges, which is not true anymore since elastic/x-pack-elasticsearch#2808.

Original commit: elastic/x-pack-elasticsearch@6b510d999a

docs/en/watcher/actions/index.asciidoc

@@ -73,6 +73,3 @@ a document and the index action indexes all of them in a bulk.
 
 An `_id` value can be added per document to dynamically set the ID of the indexed
 document.
-
-NOTE: The index action runs as a system user with elevated privileges, including
-permission to write all indices. 

docs/en/watcher/index.asciidoc

@@ -63,11 +63,6 @@ A full history of all watches is maintained in an Elasticsearch index. This
 history keeps track of each time a watch is triggered and records the results
 from the query, whether the condition was met, and what actions were taken.
 
-NOTE: Watches run with elevated privileges. Users mapped to the built-in
-`watcher_admin` role or any other role to which the `manage_watcher` cluster
-privilege is assigned should be reviewed and granted only to personnel with
-appropriate trust levels to read and write all indices.
-
 --
 
 include::getting-started.asciidoc[]

docs/en/watcher/input/search.asciidoc

@@ -201,6 +201,3 @@ specifying the request `body`:
 | `ctx.trigger.scheduled_time` | The time this watch was supposed to be triggered.
 | `ctx.metadata.*`             | Any metadata associated with the watch.
 |======
-
-NOTE: The search input runs as a system user with elevated privileges, including
-permission to read all indices.