Dashed attributes break tag value filtering

[joe-elliott]

Describe the bug
If there is an attribute name present in the traceql string that contains dashes the filtered attribute endpoint fails to parse and returns all available values.

Before this fix the same situation would cause the endpoint to return a 500.

Prior to the fix the frontend would log an error like:

level=warn ts=2024-03-04T17:32:31.858979597Z caller=server.go:2136 traceID=5497e866a459a41193a3203d812bc5ed msg="GET /tempo/api/v2/search/tag/resource.service.name/values?q=%7Bspan.is-from-foo%20%3D%20true%20%26%26%20resource.service.name%3D%7D (500) 18.514115ms Response: \"upstream: (500) error querying ingesters in Querier.SearchTagValues: failed to execute f() for 10.201.19.188:9095: rpc error: code = Unknown desc = unexpected error searching head block (6136939e-4458-4527-95c8-3b25af01f09f): parse error at line 1, col 2: syntax error: unexpected IDENTIFIER\\n\"