Alter event_reader definition

[theresamariaM]

The event_reader definition was altered to remove leading and trailing white spaces from the event types if they are a string.

[theresamariaM]

Previously the event_reader definition did not allow filtering multiple event types if an event had a leading or trailing whitespace after a comma. Example: types = "link leave, link enter" would have resulted in only reading the link leave event. While entering types = "link leave,link enter" would have resulted in reading both events. Therefore, the definition was altered to remove leading and trailing whitespaces.

[rakow]

PR was approved after discussing in person.