text: Title: Setting current_symbol on a Points layer does not make the next point added use this symbol.
  Body: ### 🐛 Bug Report
  
  The current_symbol parameter is expected to set the symbol for the next point in the layer, this is useful when writing callbacks to modify the appearance of points as they are added. The expected behaviour is confirmed by the description line 
  `current_symbol : Symbol
          Symbol for the next point to be added or the currently selected points.` .
  
  Inspecting the code, we see the following in `Points._set_data`
  ```
  if len(self._symbol) > 0:
      new_symbol = copy(self._symbol[-1]) 
  else:
      new_symbol = self.current_symbol
  ```
  which states that the symbol used for the new point is always the previous symbol if one is available. Equivalent logic is present for border width which indicates this bug affects that property as well, but the other point attributes have different logic which works as expected.
  
  I suggest that the new symbol should always be self.current_symbol if one is defined (which I believe is essentially all the time), only perhaps falling back to the previous symbol if appropriate. I could create a pull request but I would like some feedback on whether there is some reason for the current behaviour that I'm not aware. 
  
  ### 💡 Steps to Reproduce
  
  (Using code)
  1. Create a points layer with `symbol = 'square'`
  2. add a point
  3. deselect the point (if you skip this step then the next step will modify the current point)
  4. set the current_symbol to another value, say `'diamond'`
  5. add a new point
  
  
  
  
  ### 💡 Expected Behavior
  
  The second point will still be a square when it is expected to be a diamond. The fact that current_symbol is `'diamond'` is of no help, although if we set it again with the point selected we will finally get a diamond point.
  
  ### 🌎 Environment
  
  napari: 0.5.3
  Platform: Windows-10-10.0.22631-SP0
  Python: 3.10.14 | packaged by conda-forge | (main, Mar 20 2024, 12:40:08) [MSC v.1938 64 bit (AMD64)]
  Qt: 5.15.8
  PyQt5: 5.15.9
  NumPy: 2.0.2
  SciPy: 1.14.1
  Dask: 2024.8.2
  VisPy: 0.14.3
  magicgui: 0.8.3
  superqt: 0.6.7
  in-n-out: 0.2.1
  app-model: 0.2.8
  npe2: 0.7.7
  
  OpenGL:
    - GL version:  4.6.0 NVIDIA 560.76
    - MAX_TEXTURE_SIZE: 32768
    - GL_MAX_3D_TEXTURE_SIZE: 16384
  
  Screens:
    - screen 1: resolution 1920x1080, scale 1.0
    - screen 2: resolution 2048x1152, scale 1.0
  
  Optional:
    - numba: 0.60.0
    - triangle not installed
    - napari-plugin-manager: 0.1.0
  
  Settings path:
    - C:\Users\dbarton\AppData\Local\napari\napari_dc6d252616b39fa2639fd92f910f7b9647b9362c\settings.yaml
  Plugins:
    - napari: 0.5.3 (81 contributions)
    - napari-console: 0.0.9 (0 contributions)
    - napari-manual-tracking: 0.0.1 (8 contributions)
    - napari-skimage-regionprops: 0.10.1 (2 contributions)
    - napari-svg: 0.2.0 (2 contributions)
    - napari-tools-menu: 0.1.19 (0 contributions)
  
  ### 💡 Additional Context
  
  _No response_