Bump active_record_union from 1.3.0 to 1.4.0 (#4285)

Bumps [active_record_union](https://github.com/brianhempel/active_record_union) from 1.3.0 to 1.4.0.
- [Commits](https://github.com/brianhempel/active_record_union/commits)

---
updated-dependencies:
- dependency-name: active_record_union
  dependency-version: 1.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -82,8 +82,8 @@ GEM
       addressable
     active_median (0.6.0)
       activesupport (>= 7.1)
-    active_record_union (1.3.0)
-      activerecord (>= 4.0)
+    active_record_union (1.4.0)
+      activerecord (>= 6.0)
     active_utils (3.6.0)
       activesupport (>= 4.2)
       i18n
@@ -142,7 +142,7 @@ GEM
       erubi (>= 1.0.0)
       rack (>= 0.9.0)
       rouge (>= 1.0.0)
-    bigdecimal (3.2.3)
+    bigdecimal (3.3.0)
     bluecloth (2.2.0)
     bonsai-elasticsearch-rails (7.0.1)
       elasticsearch-model (< 8)
@@ -411,7 +411,7 @@ GEM
     mini_magick (4.12.0)
     mini_mime (1.1.5)
     mini_portile2 (2.8.9)
-    minitest (5.25.5)
+    minitest (5.26.0)
     moneta (1.0.0)
     msgpack (1.8.0)
     multi_json (1.15.0)