programatically added metadata fields are not save to analysis json in kymfile.

[cudmore]

When adding fields to ExperimentalMetadata, we need to do the following:

• they are displaying in gui metadata editor
• when user edits, ensure they get back into kymfile meta data

When we programmatically add to ExperimentalMetadata (see below).

• The new fields populate into the metadata editor gui
• when user edit field, the change is stored in Kym_File

Bug is on save/load with new meta data:

• New metadata fields are not saved to kymfile json file? Once they are saved, need to check load?

here are new metadata fields that need to get into saved json analysis:

    depth: Optional[float] = field(
        default=None,
        metadata=field_metadata(
            editable=True,
            label="Depth",
            widget_type="number",
            grid_span=1,
        ),
    )
    branch_order: Optional[int] = field(
        default=None,
        metadata=field_metadata(
            editable=True,
            label="Branch order",
            widget_type="number",
            grid_span=1,
        ),
    )
    direction: Optional[str] = field(
        default="",
        metadata=field_metadata(
            editable=True,
            label="Direction",
            widget_type="text",
            grid_span=1,
        ),
    )