chore: Remove CoC link in templates since it's displayed by default (#…

…3390)

* Fix CoC link and add it to PR template as well

* Remove CoC links since github already displays this

.github/ISSUE_TEMPLATE/bug-report.yml

@@ -29,6 +29,3 @@ body:
     attributes:
       label: Which version of Altair are you using?
       description: Use `alt.__version__` to find out
-  - type: markdown
-    attributes:
-      value: By submitting this issue, you agree to follow our [Code of Conduct](../../CODE_OF_CONDUCT.md).

.github/ISSUE_TEMPLATE/feature-request.yml

@@ -21,6 +21,3 @@ body:
     id: alternative-solutions
     attributes:
       label: Have you considered any alternative solutions?
-  - type: markdown
-    attributes:
-      value: By submitting this issue, you agree to follow our [Code of Conduct](../../CODE_OF_CONDUCT.md).