Fix broken links and typos in docs

[Grayson-Bishop]

Fixes broken links and typos found while auditing the repo.

Broken links / punctuation

• whitepapers/federal-security/README.md - replaced dead TIC 3.0 link with the current Azure/trusted-internet-connection repo path, and changed the trailing comma to a colon before the list.
• demos/govDelivery/README.md - updated the dead developer.govdelivery.com API docs link to https://developers.govdelivery.com/.

Typos

• demos/d365-click-to-dial-teams/files/DialFromTeams.js - accomodate the avaiable -> accommodate the available
• whitepapers/copilot/files/GenAiCopilotSettings.psm1 - existance -> existence (x2)
• whitepapers/power-apps-add-custom-app-teams/README.md - the the outline -> the outline; exmaples -> examples
• demos/transcript-demo-power+azure/installation-guide.md - the the transcripts -> the transcripts; priviledges -> privileges
• demos/transcript-demo-power+azure/developer-guide.md - child low -> child flow; paramters -> parameters (x2); mutliple -> multiple