text: Title: [ENH] input to load_from_tsfile
  Body: ### Describe the feature or idea you want to propose
  
  the function ``load_from_tsfile`` assumes that the extension is not given and (not unreasonably, given the name) appends it as ".ts"
  
  ```python
  from aeon.datasets import load_from_tsfile
  full = root+classification[0]
  X,y = load_from_tsfile(full_file_path_and_name=full)
  ```
  this came up when someone gave me a file with .txt extension (but in valid data format). 
  
  ### Describe your proposed solution
  
  Might be nice to allow an extension and only append .ts if none is given? Currently it will try load .ts.ts if you pass full_file_path_and_name with .ts on the end. The code is a bit convoluted due to paths, but should be a simple change, just check if there is a file name extension, if not, append .ts, if there is, try with what is given
  
  ### Describe alternatives you've considered, if relevant
  
  _No response_
  
  ### Additional context
  
  _No response_