Adjust nginx agent backoff settings and revert request timeout (#3820) (#3828)

Cherry-pick #3820

Problem: As a result to NGINX Agent adding a wait for nginx workers to reload before updating nginx configuration, any long-lived connections would result in an excessively long wait between updating nginx configurations. This cause delays in NGF and on NGINX Plus, could cause a dropping of traffic if there was a wait between updating the configuration and updating the NGINX Plus upstreams.

Solution: Adjust the NGINX Agent reload configuration to lower the maximum wait time. Reverted the test request timeout duration back to 10 seconds.

Testing: Ran the SnippetsFilter functional test a couple of times and verified when there was a long-lived connection blocking on of the test cases, it went from a 27 second timeout -> 3 second. Also deployed nginx and verified the agent configuration was in there.

Author: bjee19

internal/controller/provisioner/templates.go

@@ -89,4 +89,13 @@ collector:
             "ngf":
                 receivers: ["host_metrics", "nginx_metrics"]
                 exporters: ["prometheus"]
-{{- end }}`
+{{- end }}
+data_plane_config:
+    nginx:
+        reload_backoff:
+            initial_interval: .5s
+            max_interval: 1.5s
+            max_elapsed_time: 3s
+            randomization_factor: 0.5
+            multiplier: 1.5
+`