BAU: remove aws-sdk-mock and sinon

There is a critical vunerability[1] in a package which both these
depenencies depend on. Currently there is no fix available, however
these either:
- In the case of the SDK mocks, a nice to have not a required
- In the case of sinon, not used
- Both are just testing dependecies

So I have dedcided to remove them, given the npm audit check is
currently blocking.

[1]- GHSA-9wv6-86v2-598j

backend/api/package.json

@@ -17,13 +17,9 @@
     "@aws-sdk/util-dynamodb": "^3.624.0",
     "@aws-lambda-powertools/logger": "2.6.0",
     "axios": "^1.7.4",
-    "esbuild": "^0.23.0",
-    "sinon": "^17.0.1"
+    "esbuild": "^0.23.0"
   },
   "devDependencies": {
-    "@types/sinon": "^17.0.3",
-    "aws-sdk-client-mock": "^4.0.0",
-    "aws-sdk-client-mock-jest": "^4.0.0",
     "axios-mock-adapter": "^2.0.0"
   }
 }

express/package.json

@@ -43,8 +43,6 @@
     "nodemon": "^3.0.1",
     "sass": "^1.60.0",
     "typescript": "^5.5.2",
-    "uglify-js": "^3.19.2",
-    "aws-sdk-client-mock": "^4.0.0",
-    "aws-sdk-client-mock-jest": "^4.0.0"
+    "uglify-js": "^3.19.2"
   }
 }