Prevent form submission in CloudPebble text prompt
Prevent form submission in CloudPebble text prompt

At the moment, if you open a dialog box which uses CloudPebble.Prompts.Prompt, enter some text, and press enter, the page reloads. This is obviously not good or expected. 

This patch fixes the problem by preventing the default form submission behaviour.
pebble/cloudpebble,thunsaker/cloudpebble,pebble/cloudpebble,thunsaker/cloudpebble,pebble/cloudpebble,thunsaker/cloudpebble,thunsaker/cloudpebble,pebble/cloudpebble,pebble/cloudpebble