fix: flakey test for EndpointTraceItemAttributeNames

[kylemumma]

The bug:

I was querying for the attributes and they look something like this

a_tag_1
a_tag_2
...
a_tag_30
http.status
sentry.environment
...

The a_tag attributes I created and know where they're coming from. The others like http.status idk where they come from, and it turns out that they will be different on the local machine and in CI. I hard coded them to what they are on my local machine but they were different in CI sometimes which caused the tests to fail.

The way previous tests handled this was only validating the first 10

a_tag_1
...
a_tag_10

so they never encountered the changing attributes like http.status. But I didnt like this too much since its ignoring a lot of the other results (like 11 through 30).

I decided to solve the bug by validating only all the a_tag and allowing any arbitrary extra attributes

a_tag_1
...
a_tag_30

(so now http.status can be there, or not it doesnt matter)