persist function_x_graph id, re #10750

[apeters]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

Issues Solved

#10750

Checklist

• Unit tests pass with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Ticket Background

• Sponsored by:
• Found by: @
• Tested by: @
• Designed by: @

Further comments

[apeters]

To test this, import a graph that includes a reference to a functions_x_graphs.
Then export that graph and compare the .json to the graph you just imported. Notice that before the change the functions_x_graphs id changed and after the fix is has the same id as what was imported.

[johnatawnclementawn]

Looks good to me 👍🏼