Rename log file for Secret push protection

Related issue: #462289

What does this MR do and why?

We are renaming the log events file used for Secret Push Protection feature from secret-detection.log to secret_push_protection.log. This is done to better reflect the feature's name.

Context: The feature was recently renamed from Pre-receive Secret Detection to Secret Push Protection.

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N/A

How to set up and validate locally

1. Enable Secret push protection feature

pry(main)> Gitlab::CurrentSettings.update!(pre_receive_secret_detection_enabled: true) # to ensure feature is enabled instance-wide
pry(main)> project = Project.find(PROJECT_ID)
pry(main)> Feature.enable(:pre_receive_secret_detection_push_check, project) 

OR apply this patch to disable checks

diff --git a/ee/lib/gitlab/checks/secrets_check.rb b/ee/lib/gitlab/checks/secrets_check.rb
index 00b6743998d7..810354d7889e 100644
--- a/ee/lib/gitlab/checks/secrets_check.rb
+++ b/ee/lib/gitlab/checks/secrets_check.rb
@@ -93,8 +93,7 @@ def validate!
       # GitLab.com projects. For progress, follow
       # https://gitlab.com/groups/gitlab-org/-/epics/12729
       def run_pre_receive_secret_detection?
-        Gitlab::CurrentSettings.current_application_settings.pre_receive_secret_detection_enabled &&
-          (enabled_for_gitlabcom_project? || enabled_for_dedicated_project?)
+        true
       end
 
       def enabled_for_gitlabcom_project?

2. In the GDK setup, locate the new log file name at gitlab/log/secret_push_protection.log