Changes

Added a new optional title field to social media links. This title is primarily intended to be used for the "Other" service type. We need to be able to distinguish between the various channels. Nonetheless, the title input can also be used to provide multiple instances of any other channel type.

Validation changes:

• We now validate for unique title as well (URL must also be unique from before).
• Channel names can now be repeated, provided their titles are distinct.
• The "Other" channel does not behave in any way differently from the rest of the channels. We won't allow multiple "Other" entries unless they have different titles. A valid scenario is if one "Other" channel has no title and the other does.
• We do not validate title uniqueness scoped to the channel, but globally - we will not allow a repeated title even if it is across different channels.
• If there are channels that match, and their titles match, we'll only render a single error for the titles matching.

Generally followed approach in previous PR, except for setting required on the schema - feels unnecessary since the validation for this is custom.

Also added a locale override for the error label. The previous code rendered the old model-attribute-based label in the error summary, which no longer matches what we show on the form, creating a confusing experience for the user. We could have just changed the json config to change the attribute, but we now have live data using social_media_links, so that's no longer possible.

Testing

Description	Screenshot
Valid - Two channels with different titles - valid
Valid - Two "Other" channels with different titles
Valid - Title is optional
Invalid - Channel must be unique if no titles provided
Valid - Channel must be unique when "Other" selected, if no titles provided
Valid - Title must be unique (same channel example)
Valid - Title must be unique across all channels
Frontend rendering
Content item payload
Before / After label changes

Jira