[Mappings editor] Scaled float has wrong default value

[alisonelizabeth]

Kibana version:
7.7-BC1

Describe the bug:
Scaling factor defaults to 0, but help text indicates value must be greater than zero.

Steps to reproduce:

1. Create an index template and navigate to the "Mappings" step.
2. Add a scaled float field (numeric type).
3. Scaling factor input has a default value of 0, even though the help text indicates the value must be greater than 0.

Expected behavior:
I would expect there to be no default value, or for it to be >0.

Screenshots (if relevant):

[elasticmachine]

Pinging @elastic/es-ui (Team:Elasticsearch UI)