[camera][ge2d] Add const to copy assignment

llvm/llvm-project#89652 made
std::pair trivially copyable if its members are, and
it caused the following issue: "error: the parameter
for this explicitly-defaulted copy assignment operator
is const, but a member or base requires it to be
non-const". This patch adds const to copy assignment
operator to fix the issue.

Bug: 354627057
Change-Id: Ic3b4db830502c9a1ef5260e7b15dd24cb9ced783
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1086536
Fuchsia-Auto-Submit: Gulfem Savrun Yeniceri <[email protected]>
Reviewed-by: Matt Thiffault <[email protected]>
Commit-Queue: Auto-Submit <[email protected]>

src/camera/drivers/hw_accel/ge2d/ge2d_task.h

@@ -27,7 +27,7 @@ class ScopedCanvasId {
   ScopedCanvasId(const ScopedCanvasId&) = delete;
 
   ScopedCanvasId& operator=(ScopedCanvasId&& other);
-  ScopedCanvasId& operator=(ScopedCanvasId&) = delete;
+  ScopedCanvasId& operator=(const ScopedCanvasId&) = delete;
 
   ~ScopedCanvasId() { Reset(); }