refactor: update the schema link for copilot extensions

[huimiu]

Change the schema URL to the following link:

• Declarative Copilot: https://aka.ms/json-schemas/copilot/declarative-agent/v1.0/schema.json
• Plugin: https://aka.ms/json-schemas/copilot/plugin/v2.1/schema.json

Involving the following templates:

• API Plugin from scratch (None auth, API Key, AAD, OAuth).
• API Plugin from existing API.
• Basic Declarative Copilot.
• Declarative Copilot with a plugin (None auth, API Key, AAD, OAuth).
• Declarative Copilot with a plugin from existing API.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 94.61%. Comparing base (e396e30) to head (4e6155c). Report is 2 commits behind head on release/5.10.0.

Additional details and impacted files

[](https://app.codecov.io/gh/OfficeDev/teams-toolkit/pull/12387?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=OfficeDev) ```diff @@ Coverage Diff @@ ## release/5.10.0 #12387 +/- ## =============================================== Coverage 94.61% 94.61% =============================================== Files 582 582 Lines 34494 34494 Branches 6752 6835 +83 =============================================== Hits 32638 32638 Misses 1582 1582 Partials 274 274 ``` | [Files with missing lines](https://app.codecov.io/gh/OfficeDev/teams-toolkit/pull/12387?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=OfficeDev) | Coverage Δ | | |---|---|---| | [packages/spec-parser/src/constants.ts](https://app.codecov.io/gh/OfficeDev/teams-toolkit/pull/12387?src=pr&el=tree&filepath=packages%2Fspec-parser%2Fsrc%2Fconstants.ts&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=OfficeDev#diff-cGFja2FnZXMvc3BlYy1wYXJzZXIvc3JjL2NvbnN0YW50cy50cw==) | `100.00% <ø> (ø)` | |