Support enterprise uri only for vscode-pull-request-github

[Changqing-JING]

Now I have a problem, my github repo is at enterprise server "https://example-github-enterprise.com"

And my copilot is at another enterprise server:
https://xxx.ghe.com

Then it lead to a problem, to use github pull request plugin, I need:
"github-enterprise.uri": "https://example-github-enterprise.com"
to use copilot, I need:
"github-enterprise.uri": "https://xxx.ghe.com"

But there is the github-enterprise.uri field is a global config which impacts both vscode-pull-request-github and copilot.
Is this possible to add a enterprise.uri field inside the config of vscode-pull-request-github.