(web) Add term input field to filters bar to filter resource logs by string

[lizzthabet]

• Add support for filtering log spans based on a string input that behaves like the existing source and term filters
• Add a term input field in the filter bar with a debounce delay; (this does behave a tiny bit quirky which i outlined in a code note. I think this is probably okay for mvp, but happy to chat more in-depth if needed.)

Styles and tests are still a wip, but otherwise code is ready for review.

Term input field:

Filtering logs by term and level filters:

Closes ticket #12046

[landism]

The epic and docs say:

1. you can filter by logs span EXCLUDING [term]
2. the search term is a raw string unless surrounded by //, in which case it's a regexp

Are these still planned?

[lizzthabet]

The epic and docs say:

1. you can filter by logs span EXCLUDING [term]

2. the search term is a raw string _unless_ surrounded by `//`, in which case it's a regexp

Are these still planned?

They are! I broke the epic into smaller stories, so this first one is #12046 and just covers the string search. I was planning to do the other tickets (including regexp) in the epic as fast follows. (But also lmk if there's a more preferable way for me to merge in this work.)

[landism]

Looking pretty good!

[hyu]

Nice! It took me a little while to read through this code, and I think the PR would have been a little easier to understand if it was somehow split into more PRs. (e.g., separate PR for RegEx functionality / debouncing). I appreciate your comments, like those on debouncing, since that did help me understand the code better.

I added a note re: a fix for the width change on the input that Matt also noticed.