[Helm] fix typos in parameter descriptions (#7527)

**What this PR does / why we need it**:

Fixes typos in metrics-related Helm chart parameter descriptions.

**Which issue(s) this PR fixes**:
Fixes #<issue number>

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the `CONTRIBUTING.md` guide
- [x] Documentation added
- [x] Tests updated
- [x] `CHANGELOG.md` updated
- [x] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/upgrading/_index.md`

docs/sources/installation/helm/reference.md

@@ -1978,7 +1978,7 @@ null
 		<tr>
 			<td>monitoring.serviceMonitor.metricsInstance.annotations</td>
 			<td>object</td>
-			<td>MerticsInstance annotations</td>
+			<td>MetricsInstance annotations</td>
 			<td><pre lang="json">
 {}
 </pre>
@@ -1996,7 +1996,7 @@ true
 		<tr>
 			<td>monitoring.serviceMonitor.metricsInstance.labels</td>
 			<td>object</td>
-			<td>Additional MatricsInstance labels</td>
+			<td>Additional MetricsInstance labels</td>
 			<td><pre lang="json">
 {}
 </pre>

production/helm/loki/values.yaml

@@ -635,9 +635,9 @@ monitoring:
     metricsInstance:
       # -- If enabled, MetricsInstance resources for Grafana Agent Operator are created
       enabled: true
-      # -- MerticsInstance annotations
+      # -- MetricsInstance annotations
       annotations: {}
-      # -- Additional MatricsInstance labels
+      # -- Additional MetricsInstance labels
       labels: {}
       # -- If defined a MetricsInstance will be created to remote write metrics.
       remoteWrite: null