Learning path subscription email fix

[fbacall]

Summary of changes

• Fixes a ActionView::Template::Error trying to render the email template when sending a user a digest email for a learning path subscription.
• Added back the underline to links in the HTML email to make it obvious they are clickable.

Motivation and context

Error reported via Sentry in production.

Checklist

• I have read and followed the CONTRIBUTING guide.
• I confirm that I have the authority necessary to make this contribution on behalf of its copyright owner and agree
  to license it to the TeSS codebase under the
  BSD license.

[Copilot]

Pull Request Overview

This PR fixes a bug in the learning path subscription email functionality that was causing a ActionView::Template::Error in production. The fix ensures proper template rendering and improves email link styling.

• Replaced dynamic partial rendering with conditional logic to avoid template errors for learning paths
• Added conditional checks to prevent collection-related functionality from appearing in learning path emails
• Restored underline styling to email links for better usability

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
app/mailers/subscription_mailer.rb	Updates subject line to use localized resource names instead of hardcoded types
app/views/subscription_mailer/digest.html.erb	Replaces dynamic partial rendering with conditional logic and adds type checks for collections
app/views/subscription_mailer/digest.text.erb	Adds type check to prevent collection functionality for non-supported types
app/views/subscription_mailer/_resources.html.erb	Removes text-decoration:none and adds conditional check for description method
app/views/subscription_mailer/_events.html.erb	Removes text-decoration:none to restore underlines on links
test/mailers/subscription_mailer_test.rb	Adds comprehensive test for learning path digest email functionality
test/mailers/previews/subscription_mailer_preview.rb	Adds preview method for learning path digest emails
test/fixtures/subscriptions.yml	Adds test fixture for learning path subscriptions
test/controllers/subscriptions_controller_test.rb	Updates test to use dynamic count instead of hardcoded value

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[Copilot]

Using respond_to? for feature detection is fragile and can hide real issues. Consider using a more explicit check like result.is_a?(Material) or checking if the result has a description attribute directly with result.try(:description) if using Rails.

Suggested change

	<% if result.respond_to?(:description) %>
	<% if result.try(:description) %>