descriptive metadata spreadsheet: ignore form.type and/or form.source if form.value not provided

[andrewjbtw]

When importing a descriptive metadata spreadsheet, if any of the cells include data for

form*.type

and

form*.source.value

but do not include a corresponding value for

form*.value

then do not import the form*.type and form*.source.value metadata into the Cocina.

The presence of form.source and/or form.type metadata without a corresponding form.value in the Cocina prevents a druid from being indexed. This makes it very difficult to understand the processing status of the druid and creates a complex remediation task to fix the Cocina.

Related HB error: https://app.honeybadger.io/projects/49898/faults/95491637

Example spreadsheet data that will cause a problem

In the example below, data imported from both rows will result in indexing errors. Both druids have one problem in common:

form4.source.value and form4.type have data but there's no column for form4.value - compare with the data for the form3.* fields, which have three columns.

Additionally, the second row has two more problems:

1. form1.type has data but form1.value is empty
2. form2.type has data but form2.value is empty

form1.type	form1.value	form2.type	form2.value	form3.source.value	form3.type	form3.value	form4.source.value	form4.type	form5.type	form5.value
genre	Record of proceedings	genre	Transcript	MODS resource types	resource type	text	MODS resource types	resource type	extent	60 pages
genre		genre		MODS resource types	resource type	mixed material	MODS resource types	resource type	extent	233 pages