templates/cypress-tests: Fix code coverage data generation

swh-web assets were not compiled in test mode and thus istanbul babel
plugin (generating coverage data) were not included in the generated
js files.

Coverage report is now correctly generated and coverage info for js
files are now properly displayed in Phabricator Diff UI.

templates/cypress-tests: Fix uploaded mochawesome HTML report display

Using the includes parameter of publishHTML pipeline step is no longer
needed and prevents proper display of the mochawesome HTML report in
Jenkins Web UI.