[Security Solution] Alert Page Filters do not respect the local storage values across upgrades

[logeekal]

Describe the bug:

Alert Page Filters do not respect the local storage values across upgrades. This has happened because of changes in this line in this PR

Kibana/Elasticsearch Stack version:

8.18.0

Functional Area (e.g. Endpoint management, timelines, resolver, etc.):

Alert Page

Steps to reproduce:

1. Go to a version before 8.15 say 8.10.
2. Load up some Alert data.
3. Go to Alert page and customize alert page filters
4. Upgrade to 8.18.0.
5. Changes in Alert Page filters will be lost and reset as default.

Current behavior:
Changes in Alert Page filters are lost and reset as default. A new localstorage key is created ignoring the previous one.

Expected behavior:
Old local storage data should be migrated to the new format so the old user saved can be retained.

Screenshots (if relevant):

Errors in browser console (if relevant):

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

Any additional context (logs, chat logs, magical formulas, etc.):

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)