fix(ui): Same filter can be applied multiple times

[kratosmy]

What changes are being made and why?

closes #6028

How the changes have been QAed?

[kratosmy]

@anna-geller could you please help review?

[anna-geller]

I actually thought the way to implement it would be to make the namespace dropdown not available if one namespace filter has already been added

So more like disabling the filtering option instead of raising an error - WDYT? No strong opinions

For code review, Milos assigned himself 👍

[kratosmy]

I actually thought the way to implement it would be to make the namespace dropdown not available if one namespace filter has already been added

So more like disabling the filtering option instead of raising an error - WDYT? No strong opinions

For code review, Milos assigned himself 👍

Good point, actually I didn't particularly consider the business context， but as you said, If multiple namespaces do not exist, disabling the filter should be better.

[MilosPaunovic]

Actually, I think the best solution here would be to, if, for example, you already have a namespace filter selected, and considering the namespace filter has multiple: false, still allow the ability to choose the namespace but to replace the existing value. WDYT @anna-geller?

[anna-geller]

Great idea Milos! 👍