models (core): separate MessageEditData from MessageEdition:

`MessageEditData` is used to carry a new `MessageData` when an edition has happened, while
`MessageEdition` is used to send changes to do for a new edition.

libervia/backend/models/core.py

@@ -16,9 +16,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from typing import Annotated, Literal
-
-from pydantic import BaseModel, Field, validator
+from pydantic import BaseModel, Field
 
 
 class MessageData(dict):
@@ -34,31 +32,19 @@ class MessageUpdateData(BaseModel):
         super().__init__(**kwargs)
 
 
-class MessageEditData(MessageUpdateData):
-    message: dict[str, str] | None = Field(
-        None,
-        description=(
-            "Updated message content, can be in several languages (key is language code "
-            'or "" for default)'
-        ),
-    )
-    subject: dict[str, str] | None = Field(
-        None,
-        description=(
-            "Updated subject of the message, can be in several languages (key is "
-            'language code or "" for default)'
-        ),
-    )
-    mess_type: str | None = Field(
-        None,
-        description=(
-            "Updated type of the message (cf RFC 6121 §5.2.2) + C.MESS_TYPE_INFO (system "
-            "info)"
-        ),
-    )
+class MessageEditData(MessageData):
+    """Data used when a new message edition has been received"""
+    pass
 
 
 class MessageReactionData(MessageUpdateData):
     reactions: dict[str, list[str]] = Field(
         description="Reaction to reacting entities mapping"
     )
+
+
+class MessageEdition(BaseModel):
+    """Data used to send a message edition"""
+    message: dict[str, str]
+    subject: dict[str, str] = Field(default_factory=dict)
+    extra: dict[str, str] = Field(default_factory=dict)