[CardDAV] Multiple lines in Street are joined to one line with ","

Describe the bug

When a CardDAV client like DAVx⁵ uploads a contact with multiple lines in a field, for instance in the street, it uploads:

ADR:;;Street Line1,Street Line2;…

The lines are separated by ,; see RFC 6.3.50 ADR:

The text components are separated by the SEMICOLON character (U+003B). Where it makes semantic sense, individual text components can include multiple text values (e.g., a "street" component with multiple lines) separated by the COMMA character (U+002C).

On Android, this is regularly the case because most contacts apps put the whole address into the street field, so that it can easily consist of multiple lines.

When such a vCard is uploaded to Nextcloud, Nextcloud Contacts shows it with ",":

However, it should show the lines separately.

Steps to reproduce

Upload a vCard with multiple lines with curl:

cat >multiple-lines.vcf <<EOF
BEGIN:VCARD
VERSION:4.0
UID:0271ceac-d598-4b28-837e-906fa3d4f064
FN:Address Tester
N:Tester;Address;;;
ADR:;;1,2,3,4;;;;
END:VCARD
EOF
curl -nvT multiple-lines.vcf 'https://cloud.example.com/remote.php/dav/addressbooks/users/test/931ba8fd-f3eb-4a9d-bed4-3109b9c64616/multiple-lines.vcf'

(or upload a contact with multiple lines in the street for instance with DAVx⁵)

Expected behavior

• street and ideally other fields should support multiple lines
• line breaks in vCards (,) should be handled correctly

Actual behavior

• street has only one line
• line breaks in vCards (,) are not handled correctly and result in an unreadable single-line text

Contact version

4.2.1

Operating system

No response

PHP engine version

No response

Web server

No response

Database

No response

Additional info

Somehow related to https://github.com/nextcloud/contacts/issues/72

No source file or test is named. Start by reproducing the upload with the provided curl command and vCard fixture, then trace how the CardDAV ADR value is parsed and rendered; done means street lines appear separately instead of being joined with commas, with other applicable fields handled correctly.