[BrokenLinksH2] -- update LUIS REST API doc endpoints

[WilliamAntonRohm]

This PR fixes 174 broken links in this article:

• Language Understanding (LUIS) Samples

169 links were updated for v3.0's new docs location, for example:

• from: https://github.com/azure-samples/cognitive-services-language-understanding/blob/master/westeurope.dev.cognitive.microsoft.com/docs/services/luis-programmatic-apis-v3-0/operations/Settings_Update
• to: https://docs.microsoft.com/en-us/rest/api/cognitiveservices-luis/authoringv3.0preview/settings/update

The remaining 5 links were updated for v2.0's, for example:

• from: https://westus.dev.cognitive.microsoft.com/docs/services/5890b47c39e2bb17b84a55ff/operations/5ade526ad5b81c209ce2e5a4
• to: https://westus.dev.cognitive.microsoft.com/docs/services/5890b47c39e2bb17b84a55ff/operations/5ade084ad5b81c209ce2e597

[WilliamAntonRohm]

Global effort to fix broken links

@aahill, @dlepow, @v-jaswel, @diberry, @v-hearya -- I found your names as Microsoft contributors to this article. Please excuse my wide net here; only one volunteer is needed.

The Content & Learning team is fixing broken links on docs.microsoft.com for the rest of H2. This effort will eliminate potential accessibility, security, and usability issues. This PR includes only link fixes and does not change other content. Please review within five business days and merge, or comment in the PR with any changes you'd like to see. Thanks!