fix: delete all custom tables when subsite deleted from multisite

[ravinderk]

Bug Report

User Story

As an admin, I expect the plugin to delete all custom table when I will delete subsite with Give installed.

Current Behavior

Currently, only the donor's related custom table will remove when to delete subsite.

Expected Behavior

All custom table must be deleted.

Bug Type

• This bug describes functionality that once worked as expected in version X.X.X.
• This bug describes functionality that never worked as expected.
• I am not sure whether this functionality ever worked as expected.

Steps to Reproduce

1. Set subsite in multisite
2. Make sure Give network activated.
3. Delete subsite.

Acceptance Criteria

• Add all missing DB class object: https://github.com/impress-org/give/blob/release/2.3.0/includes/install.php#L211
• Make sure all custom table removed after deleting a subsite