Fix project table lock leaking to other tests

We resume the fiber if it's still alive because some tests under this
context do not call resume and a dangling fiber would mean that the
projects table will still be locked

spec/lib/gitlab/database/with_lock_retries_spec.rb

@@ -54,6 +54,10 @@ RSpec.describe Gitlab::Database::WithLockRetries do
         lock_fiber.resume # start the transaction and lock the table
       end
 
+      after do
+        lock_fiber.resume if lock_fiber.alive?
+      end
+
       context 'lock_fiber' do
         it 'acquires lock successfully' do
           check_exclusive_lock_query = """

spec/tasks/gitlab/pages_rake_spec.rb

@@ -2,7 +2,7 @@
 
 require 'rake_helper'
 
-RSpec.describe 'gitlab:pages:migrate_legacy_storagerake task', quarantine: 'https://gitlab.com/gitlab-org/gitlab/-/issues/300123' do
+RSpec.describe 'gitlab:pages:migrate_legacy_storagerake task' do
   before(:context) do
     Rake.application.rake_require 'tasks/gitlab/pages'
   end