gstreamer: pad: Remove "caps" property getter

Only only leave the notify signal connection function. The property
getter is the same as `current_caps()`, which is more lightweight.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1345>

gstreamer/Gir.toml

@@ -1761,6 +1761,11 @@ manual_traits = ["PadExtManual"]
     # Has a proper getter
     ignore = true
 
+    [[object.property]]
+    name = "caps"
+    # Same as `current_caps()`
+    generate = ["notify"]
+
 [[object]]
 name = "Gst.PadDirection"
 status = "generate"

gstreamer/src/auto/pad.rs

@@ -495,10 +495,6 @@ pub trait PadExt: IsA<Pad> + sealed::Sealed + 'static {
         }
     }
 
-    fn caps(&self) -> Option<Caps> {
-        ObjectExt::property(self.as_ref(), "caps")
-    }
-
     #[doc(alias = "linked")]
     fn connect_linked<F: Fn(&Self, &Pad) + Send + Sync + 'static>(&self, f: F) -> SignalHandlerId {
         unsafe extern "C" fn linked_trampoline<