.github/workflows: allow codecov to report without failing CI build

### Describe Your Changes

The `fail_ci_if_error` flag only affects the upload step and does not
control
Codecov's status checks (e.g., codecov/patch, codecov/project). My prior
tests
did not surface this behavior.

Switched to 'informational' mode per Codecov docs to avoid blocking CI.
See:

https://docs.codecov.com/docs/common-recipe-list#set-non-blocking-status-checks

Tested in https://github.com/VictoriaMetrics/VictoriaMetrics/pull/9146

Follow up on
https://github.com/VictoriaMetrics/VictoriaMetrics/pull/9139,
52022e482c

.github/workflows/main.yml

@@ -91,7 +91,6 @@ jobs:
         uses: codecov/codecov-action@v5
         with:
           files: ./coverage.txt
-          fail_ci_if_error: false
 
   integration-test:
     name: integration-test

codecov.yml

@@ -0,0 +1,9 @@
+# see https://docs.codecov.com/docs/common-recipe-list#set-non-blocking-status-checks
+coverage:
+  status:
+    project:
+      default:
+        informational: true
+    patch:
+      default:
+        informational: true