Right-click filter appended twice to Zed pipeline

[philrz]

Repro is with Zui commit cabf2d9.

During the course of normal app testing I stumbled onto what I show in the attached video where right-clicking on a value and selecting Filter == Value appended it twice to the Zed pipeline in my editor. So far I've only been able to reliably reproduce it if I've first done fuse to the data.

Repro.mp4

[philrz]

Verified in Zui commit 9f091b6.

I've confirmed via binary search that this was fixed by the changes in #2895. Repeating the original repro steps, the filter is now only appended once even after applying fuse.

Verify.mp4

Thanks @jameskerr!