Parser: Fix ConditionalElementMultipleTagsError on valid templates

[marcoroth]

This pull request updates the conditional element analysis passes to no longer produce false ConditionalElementMultipleTagsError errors on valid templates containing complete HTML elements inside ERB control flow branches.

The following template now parses without any errors:

<% if true %>
  <% if true %>
    <div>
      <div></div>
      <% if true %><% end %>
    </div>
  <% else %>
    <div></div>
  <% end %>
<% end %>

Related #1153
Related #1146
Related #1208

Resolves #1239

[pkg-pr-new]

npx https://pkg.pr.new/@herb-tools/formatter@1240

npx https://pkg.pr.new/@herb-tools/language-server@1240

npx https://pkg.pr.new/@herb-tools/linter@1240

commit: f916364

[github-actions]

🌿 Interactive Playground and Documentation Preview

A preview deployment has been built for this pull request. Try out the changes live in the interactive playground:

• Playground Preview
• Documentation Preview
• Website Preview

---

_{🌱 Grown from commit f916364}

---

✅ Preview deployment has been cleaned up.

[marcoroth]

https://11989abd.herb-tools.pages.dev/playground?tab=diagnostics#DwUgBAlgZmAuBOBXApmEA+AUGMpIwRTSxx2ABMIA3E0sym4Aegdrr2jiVQz2QDtyxbKWasRfADYBnHm1ysx1Wn0HDVQjEA