Institutional Templates marked Publicly Visible after creation or update

[xsrust]

Expected behaviour:
When an org-admin of an Institution creates or edits their template, it's visibility status should be retained unless explicitly set.

Actual behaviour:
The template is set to publicly_visible which effectively hides it from the Template-selection logic on the Create Plan page.

Cause:
The logic on the checkbox parsing for the org_admin/templates_controller create and update actions.