Gitlab PR decoration throws exception when no new_coverage condition is provided

[kortov]

Describe the bug
When in Sonar conditions there is no new_coverage condition (and i doubt that this condition is necessary) the plugin throws Exception. IllegalStateException("Could not find New Coverage Condition in analysis"). I guess it's kinda related to #62 but the reason of the issue lies here

sonarqube-community-branch-plugin/src/main/java/com/github/mc1arke/sonarqube/plugin/ce/pullrequest/gitlab/GitlabServerPullRequestDecorator.java

Lines 153 to 155 in 1e28de6

	QualityGate.Condition newCoverageCondition = analysis.findQualityGateCondition(CoreMetrics.NEW_COVERAGE_KEY)
	.orElseThrow(() -> new IllegalStateException("Could not find New Coverage Condition in analysis"));
	String coverageValue = newCoverageCondition.getStatus().equals(QualityGate.EvaluationStatus.NO_VALUE) ? "0" : newCoverageCondition.getValue();

The easiest solution would be

String coverageValue = analysis.findQualityGateCondition(CoreMetrics.NEW_COVERAGE_KEY)
                            .filter(condition -> condition.getStatus() != QualityGate.EvaluationStatus.NO_VALUE)
                            .map(QualityGate.Condition::getValue)
                            .orElse("0");

it's kinda duplicates the code from here

sonarqube-community-branch-plugin/src/main/java/com/github/mc1arke/sonarqube/plugin/ce/pullrequest/AnalysisDetails.java

Lines 115 to 120 in 1e28de6

	BigDecimal newCoverage =
	findQualityGateCondition(CoreMetrics.NEW_COVERAGE_KEY)
	.filter(condition -> condition.getStatus() != EvaluationStatus.NO_VALUE)
	.map(QualityGate.Condition::getValue)
	.map(BigDecimal::new)
	.orElse(null);

So may be we can put some duplicated lines into separate method from AnalysisDetails.java. I unfortunately have no idea how to implement fix nicely

Expected behavior
The plugin should not throw an exception. May be only log some info.

Screenshots
If applicable, add screenshots to help explain your problem.

Software Versions

• SonarQube Version: Version 7.9.2
• Plugin Version: custom build from master at commit 1e28de6]

[mc1arke]

Fixed in #87