Fix store debug matchers panic on regex matcher

[yeya24]

• I added CHANGELOG entry for this change.
• Change is not relevant to the end user.

Changes

Fixes #7676

ParseMetricSelector tries to copy label matchers but there is a new field re for the underlying regex and it is not copied, causing panic when calling Matches.

	for i, lm := range vs.LabelMatchers {
		matchers[i] = &labels.Matcher{
			Type:  lm.Type,
			Name:  lm.Name,
			Value: lm.Value,
		}
	}

Verification

Added a simple unit test. Without the change in this PR the test will panic when calling Matches.