Update bug report responsibilities for Product Designers (#44278)

- We often encounter bugs where the expected behavior is clear, but the
Product Development team cannot provide a specific solution. It often
requires engineer (tech lead) to understand what's broken and provide
technical details in the "To fix" section.
- Some time ago, we added a requirement to change the bug title to
reflect the expected behavior rather than what is broken. I find this
approach counterintuitive and often confusing. Additionally, I believe
we haven't consistently followed this practice, despite it being
documented.

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Co-authored-by: Noah Talerman <47070608+noahtalerman@users.noreply.github.com>

.github/ISSUE_TEMPLATE/bug-report.md

@@ -19,8 +19,8 @@ assignees: ''
 <!-- What did you see?  Paste a screenshot, include a 30s video, or write 1-2 sentences describing the issue you observed. -->
 TODO
 
-### 🛠️ To fix
-<!-- Add the expected fix here. If you're not sure, leave this blank for product to specify. If the Product Designer is unsure, add "TODO: Up to Tech Lead" and move the bug to "Ready to spec".  -->
+### 🛠️ Expected behavior
+<!-- Add the expected behavior here. If you're not sure, you can leave this blank for the Product Designer (PD) to specify. -->
 TODO
 
 ### 🧑‍💻  Steps to reproduce