Set fms_diag_accept_data

[uramirez8707]

Description

1. Ensure that fms_diag_accept_data is always set by removing return statements and setting it in the end. This is to prevent errors in debug mode in cases where fms_diag_accept_data is not set. fms_diag_accept_data is always set to .true., if there any errors in the subroutine it will crash with a FATAL.
2. Fixes the calls to send_data for a static variable in the unit tests.

Fixes #1591

How Has This Been Tested?
CI

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes

[rem1776]

If this will always return true, should we just make this a subroutine instead? I think there's only like two calls to it.

[rem1776]

thanks for making that change, looks good.