server: allow `.` in event trigger names

### Is your proposal related to a problem?

Event trigger names (used to construct SQL trigger name) can have `.`, but the server as well as the console prohibits this right now.

### Describe the solution you'd like

Allow using `.` in event trigger names by changing the regex to `^[A-Za-z]+[A-Za-z0-9_.\\-]*$`

### Describe alternatives you've considered

The alternative is to use the `replace_metadata` API to change the name of event trigger.

Start by locating the event trigger name validation in the server and console, then find the related validation tests if present. Update the regex to accept periods while retaining the existing restrictions, and verify that event trigger names containing `.` are accepted in both places without allowing invalid names.

Written by the indexing model from the issue text.