feat(frontend): pre fill selector when adding an output

[jorgeepc]

This PR adds the logic to pre-fill the selector when adding a test output based on the current selected span. It also adds a link to the expressions docs in the test output form.

Changes

• pre-fill selector in test output
• add link to expressions docs in test output form

Fixes

• fixes Add link to expressions docs in output form #1809
• fixes [Chaining V2] Prefill selector when adding an output #1807

Checklist

• tested locally
• added new dependencies
• updated the docs
• added a test

Loom

https://www.loom.com/share/fd90c71d8795404191e3de1962b83e35

[olha23]

@jorgeepc hey Jorge, can we please avoid that error message states for input? Save the test button is disable and it’s obvious that you need to enter attribute and name

[jorgeepc]

@jorgeepc hey Jorge, can we please avoid that error message states for input? Save the test button is disable and it’s obvious that you need to enter attribute and name

@olha23 yes makes sense. Let me change that 👍