[LyX/master] Remove hebrew letter document class

[Udicoudco]

On Wed, Jun 12, 2024 at 3:07 AM Richard Kimberly Heck
<rikiheck at gmail.com> wrote:
> In this case,
> removing this file will prevent a document that uses it from loading
> properly, let alone compiling. So we keep it and mark it obsolete.

A document that directly uses this layout from the settings
will be loaded with the letter layout, and the LaTeX export,
and as a consequence the pdf output will stay identical.
This is why I did the format change in this commit.

If that's still a problem I'll revert though.

Udi