[RUM] RUM dashboard crashes in incognito mode

[flash1293]

Kibana version: main

Describe the bug: Trying to access the RUM dashboard in incognito mode crashes the app

Steps to reproduce:

1. Go into incognito mode
2. Navigate to /app/ux
3. Crash

Expected behavior: Doesn't crash (like in non-incognito mode)

Screenshots (if relevant):

Errors in browser console (if relevant):

Error

Error: Cannot read properties of undefined (reading 'hasFetchStartField')
    at http://localhost:5901/9007199254740991/bundles/plugin/ux/8.0.0/ux.chunk.1.js:10538:9
    at Object.Mh [as useMemo] (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215744:119)
    at exports.useMemo (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215527:113)
    at useClientMetricsQuery (http://localhost:5901/9007199254740991/bundles/plugin/ux/8.0.0/ux.chunk.1.js:10529:69)
    at Metrics (http://localhost:5901/9007199254740991/bundles/plugin/ux/8.0.0/ux.chunk.1.js:6415:100)
    at nh (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215735:146)
    at ii (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215757:309)
    at ek (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215849:482)
    at dk (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215830:128)
    at Xj (http://localhost:5901/9007199254740991/bundles/kbn-ui-shared-deps-npm/kbn-ui-shared-deps-npm.dll.js:215829:303)

Provide logs and/or server output (if relevant):

Any additional context:

[elasticmachine]

Pinging @elastic/uptime (Team:uptime)