fix(api): accept int or str for timestamps seconds

The timestamp parameters can be passed as either a numeric string or an
integer. Update the ListingInterval type annotation from Optional[str]
to Optional[str | int] so pydantic validates both correctly.
resolve_date_range already handles both via float() conversion.

Author: André Luiz Abdalla Silveira

backend/kernelCI_app/typeModels/commonListing.py

@@ -16,11 +16,11 @@ class ListingInterval(BaseModel):
         ),
         make_default_validator(DEFAULT_INTERVAL_IN_DAYS),
     ]
-    startTimestampInSeconds: Optional[str] = Field(  # noqa: N815
+    startTimestampInSeconds: Optional[str | int] = Field(  # noqa: N815
         default=None,
         description=DocStrings.DEFAULT_START_TS_DESCRIPTION,
     )
-    endTimestampInSeconds: Optional[str] = Field(  # noqa: N815
+    endTimestampInSeconds: Optional[str | int] = Field(  # noqa: N815
         default=None,
         description=DocStrings.DEFAULT_END_TS_DESCRIPTION,
     )