feat(Sales Invoice): allow empty profile, fetch default from Customer master

[barredterra]

• Allow empty E Invoice Profile in Sales Invoice to be empty. This disables creation and validation of the e-invoice.
• Allow setting a default e-invoice profile per Customer (empty is also possible here)

[barredterra]

@Mergifyio backport version-15 version-14

[mergify]

backport version-15 version-14

✅ Backports have been created

• #77 feat(Sales Invoice): allow empty profile, fetch default from Customer master (backport #76) has been created for branch version-15
• #78 feat(Sales Invoice): allow empty profile, fetch default from Customer master (backport #76) has been created for branch version-14