prevent attachment column updates when importing budibase templates

[andz-bb]

Description

We want to be able to import apps from templates while preserving the attachment data from those template dbs. updateAttachmentColumns is great when importing an app with attachments from a file, but wrecks the attachment data in our templates which is always pointing to a public s3 bucket rather than the instance's own object storage

for example, an attachment in my template app db:

"Image":{"size":604516,"name":"amsterdam.jpg","extension":"jpg","key":"amsterdam.jpg","url":"https://prod-budi-templates.s3.eu-west-1.amazonaws.com/attachments/expense-approval/amsterdam.jpg"}

gets completely stripped out by the above function. I've added in a flag to prevent it from running when we're importing from a template rather than a file (i.e. when template.key has a value)

Launchcontrol

fix for attachments in budibase templates

[qa-wolf]

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[mike12345567]

LGTM!

[aptkingston]

Just one sneaky change needed due to how default params work, but otherwise LGTM!