This commit fixes three bugs.

1. The first bug is that the lti_version field is inappropriately hidden in the Studio author view edit menu when the selected config_type is database.

2. The second bug is that the editable_fields property of the LtiConsumerXBlock is inappropriately excluding LTI 1.3 fields when the config_type is database. The editable_fields property should include LTI 1.3 fields even when the config_type is database, because the Javascript defined in xblock_studio_view.js may want to show these fields if the user selects a different config_type in the menu. We want to support a dynamic edit menu, so these fields must be considered editable by the XBlock in order for the Javascript to be able to manipulate them.

3. The third bug is in inconsistent rendering of the Studio author view edit menu. Depending on the order in which a user selects lti_version, config_type, or lti_1p3_tool_key_mode, different sets of fields are displayed, due to the overlapping sets of rules that govern what fields should be hidden or shown for a given field selection. This commit corrects this inconsistent rendering by first showing all fields and then gradually hiding fields depending on the sets of rules, for each change to the fields.