Project/Namespace should respect header filter

[richard-cox]

Setup

• Rancher version: v2.15 and before

Describe the bug

• the header project/namespace filter contains two different modes
  • user or sytemm
    • resource on the page should be restricted by those that are either in user or system namespaces
  • explicit
    • resources should be restricted by those that are in
      • the selected projects namespaces
      • the selected namespaces
• the project/namespace list currently ignores these
• Suggestion - apply the header filter to the list
  • filtering projects / namespaces on user or system makes a lot of sense
  • filtering namespaces on N number of projects makes sense
  • filtering namespaces on N namespaces though is a bit odd, but worth the gain

To Reproduce

• nav to a cluster --> cluster --> projects/namespaces
• toggle filtering through all --> user --> system --> a project --> a namespace

Result

• list content remains unchanged regardless of value in header filter

Expected Result

• list content should be restricted by value in header filter

Additional context
Bugs in series

1. Project/Namespace should respect header filter #18693
2. [BUG] New users are created with a generated names prefixed by m- instead of u- rancher#56214 not related (i got confused between name and associated local cluster namespace)
3. User namespaces are not treated as obscure #18695
4. Resources in obscure namespaces are not filtered out from lists #18696