Update Invalid Issue section: Copilot Triage Section (non-Blazor)

[wadepickett]

An improvment is needed for the following GitHub copilot agent located here for non-blazor docs:

dotnet/AspNetCore.Docs/.github/agents/issue-triage.agent.md

The "For Invalid Issues" section needs to be softened a bit. If an issue is determined to be invalid by GitHub Copilot, we do not of course just mark the issue as invalid. The point of the triage run by GitHub Copilot is to just pull information togther and provide a report for further review beyond the issue description and any discussion, which is helpful for quickly trying to triage and determine what sprint it might fit into along with all other work.

That section currently is very black and white and assured of itself, when really it is just rasing flags for more investigation is needed.

For example that section could be reworded this way, along with an emoji change:

For Invalid Issues

# Issue Analysis: <Issue Title>

## ❓ Issue Validation
**Status:** Needs additional attention -- not actionable yet as is
**Reason:** [Possibly out of scope / May require more information / Could be product issue / Possibly already addressed]

## 📋 Explanation
<Clear explanation of why the issue cannot be addressed as documentation>

## 💡 Recommendation
* [Close with explanation]
* [Redirect to appropriate repository]
* [Request additional information]
* [Convert to discussion]

## 🔗 Alternative Resources
* [Link to relevant documentation]
* [Link to appropriate repository for product issues]

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Associated WorkItem - 540488