chat: regen Postgres schema dump for UNIQUE simplex_name indexes

Follow-up to f71c579c. The SchemaDump test runs against SQLite only;
the parallel PostgresSchemaDump suite gates on -fclient_postgres and
a running localhost PG instance, which this environment doesn't have.
Updated the Postgres schema dump by hand to mirror the migration
change (two lines: CREATE INDEX → CREATE UNIQUE INDEX).

src/Simplex/Chat/Store/Postgres/Migrations/chat_schema.sql

@@ -2193,7 +2193,7 @@ CREATE INDEX idx_contacts_grp_direct_inv_from_member_conn_id ON test_chat_schema
 
 
 
-CREATE INDEX idx_contacts_simplex_name ON test_chat_schema.contacts USING btree (user_id, simplex_name) WHERE (simplex_name IS NOT NULL);
+CREATE UNIQUE INDEX idx_contacts_simplex_name ON test_chat_schema.contacts USING btree (user_id, simplex_name) WHERE (simplex_name IS NOT NULL);
 
 
 
@@ -2373,7 +2373,7 @@ CREATE INDEX idx_groups_relay_request_group_link ON test_chat_schema.groups USIN
 
 
 
-CREATE INDEX idx_groups_simplex_name ON test_chat_schema.groups USING btree (user_id, simplex_name) WHERE (simplex_name IS NOT NULL);
+CREATE UNIQUE INDEX idx_groups_simplex_name ON test_chat_schema.groups USING btree (user_id, simplex_name) WHERE (simplex_name IS NOT NULL);