Bump io.micrometer:micrometer-registry-otlp in /modules/grafana

Bumps [io.micrometer:micrometer-registry-otlp](https://github.com/micrometer-metrics/micrometer) from 1.15.3 to 1.15.4.
- [Release notes](https://github.com/micrometer-metrics/micrometer/releases)
- [Commits](micrometer-metrics/micrometer@v1.15.3...v1.15.4)

---
updated-dependencies:
- dependency-name: io.micrometer:micrometer-registry-otlp
  dependency-version: 1.15.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

modules/grafana/build.gradle

@@ -4,7 +4,7 @@ dependencies {
     api project(':testcontainers')
 
     testImplementation 'io.rest-assured:rest-assured:5.5.6'
-    testImplementation 'io.micrometer:micrometer-registry-otlp:1.15.3'
+    testImplementation 'io.micrometer:micrometer-registry-otlp:1.15.4'
     testImplementation 'uk.org.webcompere:system-stubs-jupiter:2.1.8'
 
     testImplementation platform('io.opentelemetry:opentelemetry-bom:1.53.0')