Add CODEOWNERS for GitHub Copilot directories (#45171)

* Add CODEOWNERS for GitHub Copilot directories

* Update .github/CODEOWNERS

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Remove agents directory until one is created

* Add Ben to prompts and skills

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: mccoyp

.github/CODEOWNERS

@@ -828,6 +828,8 @@
 /.github/workflows/                                                  @Azure/azure-sdk-eng
 /.github/CODEOWNERS                                                  @lmazuel @xiangyan99 @kashifkhan @Azure/azure-sdk-eng
 /.github/copilot-instructions.md                                     @l0lawrence @praveenkuttappan @maririos
+/.github/prompts/                                                    @mccoyp @l0lawrence @benbp
+/.github/skills/                                                     @mccoyp @l0lawrence @benbp
 /sdk/pullrequest.yml                                                 @scbedd @weshaggard @benbp
 
 /.config/1espt/                                                      @benbp @weshaggard