Remove overlap from file size limit tests

Makes the instance-level file size limit set in
`push_over_http_file_size_spec` greater than the project-level limit
set in `push_rules_spec` so that when the tests are run in parallel
(e.g., on Staging) `push_rules_spec` doesn't trigger the application-
level limit, which has a different error message and therefore causes
the test to fail (even though the push is rejected because it is over
the limit).

qa/qa/specs/features/browser_ui/3_create/repository/push_over_http_file_size_spec.rb

@@ -3,6 +3,12 @@
 module QA
   context 'Create', :requires_admin do
     describe 'push after setting the file size limit via admin/application_settings' do
+      # Note: The file size limits in this test should be greater than the limits in
+      # ee/browser_ui/3_create/repository/push_rules_spec to prevent that test from
+      # triggering the limit set in this test (which can happen on Staging where the
+      # tests are run in parallel).
+      # See: https://gitlab.com/gitlab-org/gitlab/-/issues/218620#note_361634705
+
       include Support::Api
 
       before(:context) do
@@ -31,7 +37,7 @@ module QA
       end
 
       it 'push fails when the file size is above the limit' do
-        set_file_size_limit(1)
+        set_file_size_limit(2)
 
         retry_on_fail do
           expect { push_new_file('oversize_file_2.bin', wait_for_push: false) }
@@ -52,7 +58,7 @@ module QA
         output = Resource::Repository::Push.fabricate! do |p|
           p.repository_http_uri = @project.repository_http_location.uri
           p.file_name = file_name
-          p.file_content = SecureRandom.random_bytes(2000000)
+          p.file_content = SecureRandom.random_bytes(3000000)
           p.commit_message = commit_message
           p.new_branch = false
         end

qa/qa/specs/features/ee/browser_ui/3_create/repository/push_rules_spec.rb

@@ -35,6 +35,12 @@ module QA
         end
 
         it 'restricts files by name and size' do
+          # Note: The file size limits in this test should be lower than the limits in
+          # browser_ui/3_create/repository/push_over_http_file_size_spec to prevent
+          # the limit set in that test from triggering in this test (which can happen
+          # on Staging where the tests are run in parallel).
+          # See: https://gitlab.com/gitlab-org/gitlab/-/issues/218620#note_361634705
+
           large_file = [{
             name: 'file',
             content: SecureRandom.hex(1000000)