fix: update synthetics agent project id CLI option (#3333) (#3335)

(cherry picked from commit 8947fcf)

Co-authored-by: Vignesh Shanmugam <[email protected]>

docs/en/observability/synthetics-command-reference.asciidoc

@@ -108,7 +108,7 @@ Create monitors in {kib} by using your local journeys.
 
 [source,sh]
 ----
-npx @elastic/synthetics push --auth <api-key> --url <kibana-url> --project <id|name>
+npx @elastic/synthetics push --auth <api-key> --url <kibana-url> --id <id|name>
 ----
 
 [NOTE]
@@ -140,7 +140,7 @@ If you are pushing to a <<private-locations,{private-location}>>, you must use a
 To create an API key, you must be logged into {kib} as a user with the privileges described in
 <<synthetics-role-write>>.
 
-`--project <string>`::
+`--id <string>`::
 A unique id associated with your project.
 It will be used for logically grouping monitors.
 +