Stop using UrlHelper includes in integrations

What does this MR do and why?

This resolves another issue collected in Rails/IncludeUrlHelper violations (&6767 - closed), specifically Clean `include ::ActionView::Helpers::UrlHelper... (#341384 - closed)

Skipping CI for now, because in the previous MR of this series, we had 2 of 3 pipelines being redundant (initial + review + MWPS).

Locally, testing after rebasing on latest master yielded: (again)

$ bundle exec rspec spec/models/integrations/
…
Top 1 slowest examples (4.25 seconds, 1.0% of total time):
Integrations::WebexTeams behaves like chat integration #execute with wiki page events behaves like triggered Webex Teams integration calls Webex Teams API
4.25 seconds ./spec/support/shared_examples/models/chat_integration_shared_examples.rb:55
Top 1 slowest example groups:
Integrations::BaseIssueTracker
0.67364 seconds average (1.35 seconds / 2 examples) ./spec/models/integrations/base_issue_tracker_spec.rb:5
Finished in 6 minutes 54 seconds (files took 24.98 seconds to load)
1392 examples, 0 failures
Randomized with seed 58081
$ bundle exec rspec ee/spec/models/integrations/
…
Top 1 slowest examples (2.94 seconds, 2.0% of total time):
Integrations::ChatMessage::VulnerabilityMessage#attachments contains the correct attributes
2.94 seconds ./ee/spec/models/integrations/chat_message/vulnerability_message_spec.rb:48
Top 1 slowest example groups:
Integrations::ChatMessage::VulnerabilityMessage
0.44634 seconds average (3.12 seconds / 7 examples) ./ee/spec/models/integrations/chat_message/vulnerability_message_spec.rb:5
Finished in 2 minutes 25.2 seconds (files took 43.76 seconds to load)
73 examples, 0 failures
Randomized with seed 30801

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