Relates to #3728.
A handful of changes to the logs filter on Runs.
- Change "AssetMaterialization" and "Materialization" tag strings to STEP_MATERIALIZATION to match behavior of other event types. In a followup, this enum value should be changed to ASSET_MATERIALIZATION.
- Repair token string handling with respect to the URL -- if the user has typed step:, then "step" should be treated as a token instead of a value.
- Add fuzzy matching to the value segment of the typed "key:value" pair in the log filter, e.g. typing "type:mat" would display "type:STEP_MATERIALIZATION" as a suggestion.