fix: kvstore key should allow 50 characters

closes #13068

freqtrade/persistence/key_value_store.py

@@ -18,6 +18,7 @@ class ValueTypesEnum(StrEnum):
     INT = "int"
 
 
+# must be < 50 characters to fit the database column
 KeyStoreKeys = Literal[
     "bot_start_time",
     "startup_time",
@@ -37,7 +38,7 @@ class _KeyValueStoreModel(ModelBase):
 
     id: Mapped[int] = mapped_column(primary_key=True)
 
-    key: Mapped[KeyStoreKeys] = mapped_column(String(25), nullable=False, index=True)
+    key: Mapped[KeyStoreKeys] = mapped_column(String(50), nullable=False, index=True)
 
     value_type: Mapped[ValueTypesEnum] = mapped_column(String(20), nullable=False)