[BUG] Multitenancy: separate tenants cannot be used in different browser tabs

[neodescis]

Describe the bug
If I have two browser tabs open, and I select Tenant A in one tab, and then select Tenant B in the second tab, requests made in the first tab will get mapped to the tenant that was selected in the second tab. So, in the first tab, even though it says Tenant A is the current tenant, all saved objects that are pulled up will in fact be from Tenant B.

To Reproduce

• Configure Dashboards to have two or more tenants
• Change to one of those tenants (Tenant A)
• Open a new tab
• Select another tenant in the 2nd tab (Tenant B)
• Go back to the first tab and search for dashboards, visualizations, etc.

Expected behavior
The first tab should return results from Tenant A

Actual behavior
The first tab returns results from Tenant B, despite saying Tenant A is the current tenant

OpenSearch Version
2.18.0

Dashboards Version
2.18.0

Plugins

• Security

Screenshots

If applicable, add screenshots to help explain your problem.

Host/Environment (please complete the following information):

• OS: Windows 11
• Browser and version: Chrome 131

Additional context
I believe this is because the selected tenant is being saved in a cookie, which is being reused across browser tabs

[neodescis]

Realized I should have put this in the security plugin repo. Closing in favor of opensearch-project/security-dashboards-plugin#2161.