ci: don't fail build if coverage should not be reported/failure (aws#7798)

## Problem
if token is not available or the target branch is not master, then
coverage upload command will report failure

additionally, coverage upload failure should not fail the build

## Solution
suppress failure

---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: rli

buildspec/linuxTests.yml

@@ -48,7 +48,7 @@ phases:
             - VCS_COMMIT_ID="${CODEBUILD_RESOLVED_SOURCE_VERSION}"
             - CI_BUILD_URL=$(echo $CODEBUILD_BUILD_URL | sed 's/#/%23/g') # Encode `#` in the URL because otherwise the url is clipped in the Codecov.io site
             - CI_BUILD_ID="${CODEBUILD_BUILD_ID}"
-            - test -n "${CODECOV_TOKEN}" && [ "$TARGET_BRANCH" = "master" ] && ./codecov --token=${CODECOV_TOKEN} --branch=${CODEBUILD_RESOLVED_SOURCE_VERSION} --repository=${CODEBUILD_SOURCE_REPO_URL} --file=./coverage/amazonq/lcov.info --file=./coverage/toolkit/lcov.info
+            - test -n "${CODECOV_TOKEN}" && [ "$TARGET_BRANCH" = "master" ] && ./codecov --token=${CODECOV_TOKEN} --branch=${CODEBUILD_RESOLVED_SOURCE_VERSION} --repository=${CODEBUILD_SOURCE_REPO_URL} --file=./coverage/amazonq/lcov.info --file=./coverage/toolkit/lcov.info || true
 
 reports:
     unit-test: