chore(deps): remove @backstage/test-utils form dependencies

Signed-off-by: Dávid Kosztka <dkosztka@bol.com>

.changeset/odd-kings-tell.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-cost-insights': patch
+---
+
+Removed @backstage/test-utils dependency, since it was already in the devDependencies where it belongs. The main benefit is that this will exclude better-sqlite3 from the production build.

plugins/cost-insights/package.json

@@ -38,7 +38,6 @@
     "@backstage/core-plugin-api": "workspace:^",
     "@backstage/plugin-catalog-react": "workspace:^",
     "@backstage/plugin-cost-insights-common": "workspace:^",
-    "@backstage/test-utils": "workspace:^",
     "@backstage/theme": "workspace:^",
     "@material-ui/core": "^4.12.2",
     "@material-ui/icons": "^4.9.1",