fix: Erroneous warning LG file must have at least one template definition

[lei9444]

Description

root cause

1. The warning message is filtered in fix: Exclude no template definition warning in LG editor #4525, but the position can't cover all scenarios.
2. The navigation url use root projectId only, so if the lg is in skill bot, the function will generate a wrong url.

In PR

1. change the filter position
2. update the generate url function
3. the diagnostic page doesn't been used any more, so clean these codes

Task Item

closes #7934

Screenshots

[boydc2014]

glad to see code cleaning

[srinaath]

@lei9444 Can you rebase with this PR. #8141. I had done some cleanup on removing the diagnostics pages already. I hope to get my PR merged today

[cwhitten]

@lei9444 #8141 has been merged and there are now conflicts here to address

[coveralls]

Coverage increased (+0.006%) to 54.664% when pulling a30c6a9 on lei9444:navfix into 92e6b1b on microsoft:main.