LinkedIn and Pinterest's OAuth providers return the granted scope list
joined by comma (LinkedIn) or space-in-one-element (Pinterest), but
Socialite's scope splitter doesn't match either, so 'approvedScopes'
lands as a single-element array containing the whole list:
LinkedIn: ['email,openid,profile,r_basicprofile,w_member_social']
Pinterest: ['boards:read boards:write pins:read pins:write user_accounts:read']
That breaks the publish-time scope check in PublishToSocialPlatform
(array_diff does exact string compare), surfacing as
'Missing permissions: w_member_social. Please reconnect your account'
even though the scopes were actually granted at the provider.
Fix is inline at each callback — re-split before saving. Each provider
has its own quirk (LinkedIn = comma, Pinterest = space), so each
controller handles its own separator.
Tests added: callback splits the joined approvedScopes into individual
tokens for both providers.