[Observability] Fix integrations detected twice (elastic#198670)

Resolves [elastic#195912](elastic#195912)

## Summary

Fixes an issue where integrations were displayed twice in the list of
detected log files.

Co-authored-by: Joe Reuter <[email protected]>

x-pack/plugins/observability_solution/observability_onboarding/public/assets/auto_detect.sh

@@ -325,15 +325,31 @@ apply_elastic_agent_config() {
 
 read_open_log_file_list() {
   local exclude_patterns=(
-    "^\/Users\/.+?\/Library\/Application Support"
-    "^\/Users\/.+?\/Library\/Group Containers"
-    "^\/Users\/.+?\/Library\/Containers"
-    "^\/Users\/.+?\/Library\/Caches"
-    "^\/private"
+    "^\/Users\/.+?\/Library\/Application Support\/"
+    "^\/Users\/.+?\/Library\/Group Containers\/"
+    "^\/Users\/.+?\/Library\/Containers\/"
+    "^\/Users\/.+?\/Library\/Caches\/"
+    "^\/private\/"
+
+    # Integrations only ingest a subset of application logs so there are scenarios where additional
+    # log files could be detected and displayed as a "custom log" alongside the detected integration
+    # they belong to. To avoid this UX issue we exclude all log files inside application directories
+    # from the custom log file detection
+    "^\/var\/log\/nginx\/"
+    "^\/var\/log\/apache2\/"
+    "^\/var\/log\/httpd\/"
+    "^\/var\/log\/mysql\/"
+    "^\/var\/log\/postgresql\/"
+    "^\/var\/log\/redis\/"
+    "^\/var\/log\/rabbitmq\/"
+    "^\/var\/log\/kafka\/"
+    "^\/var\/log\/mongodb\/"
+    "^\/opt\/tomcat\/logs\/"
+    "^\/var\/log\/prometheus\/"
 
     # Exclude previous installation logs
-    "\/opt\/Elastic\/Agent\/"
-    "\/Library\/Elastic\/Agent\/"
+    "^\/opt\/Elastic\/Agent\/"
+    "^\/Library\/Elastic\/Agent\/"
   )
 
   # Excluding all patterns that correspond to known integrations

x-pack/plugins/observability_solution/observability_onboarding/public/assets/integrations.conf

@@ -34,9 +34,9 @@ patterns=
 title=PostgreSQL
 patterns=
     /var/log/postgresql/postgresql-*-*.log*
+    /var/log/postgresql/postgresql-*-*.csv*
     /*/postgresql-logs/*.log
     /etc/postgresql/*/main/postgresql.conf
-    /var/log/postgresql/postgresql-*-*.csv*
 
 [redis]
 title=Redis