Remove codecov config (#37420)

codecov.yml

@@ -1,27 +0,0 @@
-# Copyright (c) HashiCorp, Inc.
-# SPDX-License-Identifier: BUSL-1.1
-
-comment:
-  layout: "flags, files"
-  behavior: default
-  require_changes: true   # only comment on changes in coverage
-  require_base: yes       # [yes :: must have a base report to post]
-  require_head: yes       # [yes :: must have a head report to post]
-  branches:               # branch names that can post comment
-    - "main"
-
-coverage:
-  status:
-    project:
-      default:
-        informational: true
-        target: auto
-        threshold: "0.5%"
-    patch:
-      default:
-        informational: true
-        target: auto
-        threshold: "0.5%"
-
-github_checks:
-    annotations: false