[Bug]: Improve consistency of displaying error messages

[madhav165]

🐞 Bug Summary

1. Invalid inputs are handled differently in different places in the UI
2. Server with invalid name - shows near field
3. Tools with unsafe URL - shows as a big red ribbon in UI
4. Prompt with unsafe template - shows Internal Server error
5. Resources with invalid URI - shows a small red box at the top right

See #363 for details on how to implement

🧩 Affected Component

Select the area of the project impacted:

• mcpgateway - API
• mcpgateway - UI (admin panel)

---

🔁 Steps to Reproduce

1. Try invalid names, URLs, URIs from Tool, Prompt, Resource and Server screens
2. Check the different types of warnings given

---

🤔 Expected Behavior

1. All warnings on invalid inputs should be handled consistently
2. Internal Server errors should not be created by invalid inputs

---

[rakdutta]

The following routers were updated as part of issue #363. The corresponding PRs have been merged. Hence, closing the issue.

Add Gateway: #438
Add Servers: #501
Add Resource: #501, #555
Add Tool & Edit Tool: #569
Add Prompt & Edit Prompt: #629
Edit Gateway : #648
Edit Server and Edit Resource:#665