Improved post receive banner path matching

Resolves an issue raised in
https://gitlab.com/gitlab-org/gitlab/-/issues/216344

app/services/post_receive_service.rb

@@ -81,8 +81,12 @@ class PostReceiveService
     banner = nil
 
     if project
-      scoped_messages = BroadcastMessage.current_banner_messages(project.full_path).select do |message|
-        message.target_path.present? && message.matches_current_path(project.full_path)
+      # This provides the path in a similar manner to the frontend passing
+      # the request path, improving regex matching.
+      path = "/#{project.full_path}"
+
+      scoped_messages = BroadcastMessage.current_banner_messages(path).select do |message|
+        message.target_path.present? && message.matches_current_path(path)
       end
 
       banner = scoped_messages.last

spec/services/post_receive_service_spec.rb

@@ -264,7 +264,7 @@ RSpec.describe PostReceiveService do
 
     context "project path matches" do
       before do
-        allow(project).to receive(:full_path).and_return("/company/sekrit-project")
+        allow(project).to receive(:full_path).and_return("company/sekrit-project")
       end
 
       it "does output the latest scoped broadcast message" do