Bump govuk_app_config from 9.15.4 to 9.15.5

Bumps [govuk_app_config](https://github.com/alphagov/govuk_app_config) from 9.15.4 to 9.15.5.
- [Changelog](https://github.com/alphagov/govuk_app_config/blob/main/CHANGELOG.md)
- [Commits](alphagov/govuk_app_config@v9.15.4...v9.15.5)

---
updated-dependencies:
- dependency-name: govuk_app_config
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -293,7 +293,7 @@ GEM
       nokogiri (~> 1.12)
       rinku (~> 2.0)
       sanitize (~> 6)
-    govuk_app_config (9.15.4)
+    govuk_app_config (9.15.5)
       logstasher (~> 2.1)
       opentelemetry-exporter-otlp (>= 0.25, < 0.30)
       opentelemetry-instrumentation-all (>= 0.39.1, < 0.70.0)
@@ -368,7 +368,7 @@ GEM
       nokogiri (>= 1.6)
     invalid_utf8_rejector (0.0.4)
     io-console (0.8.0)
-    irb (1.14.1)
+    irb (1.14.2)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
     isbn_validation (1.2.2)
@@ -407,7 +407,7 @@ GEM
       addressable (~> 2.8)
       childprocess (~> 5.0)
     link_header (0.0.8)
-    logger (1.6.2)
+    logger (1.6.3)
     logstasher (2.1.5)
       activesupport (>= 5.2)
       request_store
@@ -808,7 +808,7 @@ GEM
       activesupport (>= 5.0.0)
       minitest
       nokogiri (>= 1.6)
-    rails-html-sanitizer (1.6.1)
+    rails-html-sanitizer (1.6.2)
       loofah (~> 2.21)
       nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
     rails-i18n (7.0.10)