Fixed misconfigured SnapshotManager in e2e tests

refs https://github.com/TryGhost/Toolbox/issues/210

- After updating to the newest `@tryghost/express-test`, it's dependency `@tryghost/jest-snapshot` was missmatched with the one used in Ghost itself. This caused multiple instances of SnapshotManager class in the system, which is meant to be a singleton!
- The issue was causing following error to appear: "IncorrectUsageError: Unable to run snapshot tests, current test was not configured"

package.json

@@ -184,7 +184,7 @@
   "devDependencies": {
     "@lodder/grunt-postcss": "3.1.1",
     "@tryghost/express-test": "0.5.0",
-    "@tryghost/jest-snapshot": "0.3.1",
+    "@tryghost/jest-snapshot": "0.3.2",
     "c8": "7.11.0",
     "coffeescript": "2.6.1",
     "cssnano": "5.0.17",

yarn.lock

@@ -1714,16 +1714,7 @@
   optionalDependencies:
     sharp "^0.29.0"
 
-"@tryghost/jest-snapshot@0.3.1":
-  version "0.3.1"
-  resolved "https://registry.yarnpkg.com/@tryghost/jest-snapshot/-/jest-snapshot-0.3.1.tgz#0fdc1a272cea407bb3e2af23a2ce3cd4d07431fe"
-  integrity sha512-pXxp+jigNVt3OTMFaX5BpmFufRjPj0en7cU8IAoVOkNa5Jt7cG7DL2l8QkPaMNu1GbJM6inMjqCYoeEw3ZjHIg==
-  dependencies:
-    "@tryghost/errors" "^1.2.1"
-    expect "^27.5.0"
-    jest-snapshot "^27.5.0"
-
-"@tryghost/jest-snapshot@^0.3.2":
+"@tryghost/jest-snapshot@0.3.2", "@tryghost/jest-snapshot@^0.3.2":
   version "0.3.2"
   resolved "https://registry.yarnpkg.com/@tryghost/jest-snapshot/-/jest-snapshot-0.3.2.tgz#11c20b3f8dee5918d5754634b9cef4b1ef3b6a60"
   integrity sha512-mevHniOmAuqfWKtHKtKuU/+INmYOiE4GJyuntJcTr4MncgZCtQqRCOU+EiAvUqE/BU36n9lvAfQ2j/p4Ji9bYw==