Show E2E test coverage of chainlink node binary

[lukaszcl]

This updates integration workflow to build chainlink image with cover flag to get coverage profiling during E2E tests. The E2E test coverage is shown in "Show Chainlink Node Go Coverage" workflow step. The coverage is calculated based on all executed E2E tests.

Example CI job:

Total coverage for all tests:
	github.com/smartcontractkit/chainlink/v2		coverage: 100.0% of statements
	github.com/smartcontractkit/chainlink/v2/common/client		coverage: 38.9% of statements
	github.com/smartcontractkit/chainlink/v2/common/config		coverage: 66.7% of statements
	github.com/smartcontractkit/chainlink/v2/common/fee		coverage: [18](https://github.com/smartcontractkit/chainlink/actions/runs/8743599561/job/23995064497?pr=12878#step:4:19).5% of statements
	github.com/smartcontractkit/chainlink/v2/common/fee/types			github.com/smartcontractkit/chainlink/v2/common/headtracker		coverage: 74.3% of statements
	github.com/smartcontractkit/chainlink/v2/common/headtracker/types			github.com/smartcontractkit/chainlink/v2/common/internal/utils		coverage: 57.1% of statements
	github.com/smartcontractkit/chainlink/v2/common/txmgr		coverage: 44.4% of statements
	github.com/smartcontractkit/chainlink/v2/common/txmgr/types		coverage: 63.0% of statements
	github.com/smartcontractkit/chainlink/v2/common/types		coverage: 0.0% of statements
	github.com/smartcontractkit/chainlink/v2/core		coverage: 57.1% of statements
	github.com/smartcontractkit/chainlink/v2/core/auth		coverage: 0.0% of statements
	github.com/smartcontractkit/chainlink/v2/core/bridges		coverage: 41.9% of statements
	github.com/smartcontractkit/chainlink/v2/core/build		coverage: 85.7% of statements

When Logging.show_html_coverage_report=true is set and the Chainlink Node image is built with the cover flag, an HTML coverage report will be generated for each test.

To build node image with cover flag run docker build with COVER_FLAG=true: docker buildx build --platform linux/arm64 . -t localhost/chainlink-local:develop -f ./core/chainlink.Dockerfile --build-arg COVER_FLAG=true

For now the coverage is only tracked for tests that use CleanUpTypeStandard.

• Requires Allow to pass go coverage flags to "build chainlink image" and "run test" steps chainlink-github-actions#167
• Show link to html coverage report when E2E test executed locally

[cl-sonarqube-production]

Quality Gate passed

Issues
2 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube