Persist the text format while editting the existing address.

Problem/Motivation

Currently, the text format always defaults to basic_page even if it was previously edited as a different format.

It should attempt to reuse the previous text format when editting.

Steps to reproduce

Use a text format other than basic_page, save and then reattempt to edit the same address formatter.

Proposed resolution

Reuse the existing text format saved in the config.

Remaining tasks

Provide issue fork/patch.

User interface changes

It no longer switches text formats unnecessarily.