Fixed: tighter check for valid model

[snipe]

This should honestly never ever happen, since at a the model level we check for a valid model, BUT when it does happen (assuming the user manually edited something in the database, or restored from the before times when we didn't validate as strictly) that an asset has an invalid or null model_id, this should return a friendlier error message (versus a 500 error.)

This used to work this way, but when I added the model file tab and some of the manufacturer info, it assumed that relationship was a valid one, which broke the warning and would just then return a 500 error with a Trying to get property 'uploads' of non-object at /Users/snipe/Sites/snipe-it/snipe-it/storage/framework/views error.

[what-the-diff]

PR Summary

• Update to Warning Message Text
  In message.php, the warning message 'no_association' was rewritten to provide a clearer explanation. It now states, 'WARNING! The asset model for this item is invalid or missing!'.

• Enhancements to Warning Message Display
  In view.blade.php, changes were made on how the warning message is displayed. It is now prominently highlighted, likely leading to better user attention and awareness.

• Change in Badge Display Line
  Adjustments were made to the line of code displaying the 'badge' in view.blade.php. It seems like a way to present certain counts, possibly enhancing performance or accuracy, but without further specifics, it's hard to explain the exact value here.

• Changes to Hyperlink
  The line of code that generates a hyperlink for warranty information in view.blade.php was revised, potentially improving its functionality or user experience, but more details are needed to correctly identify the specific benefit.

• Improved Conditions for Displaying Uploads
  Lastly, safeguards were bolstered in view.blade.php by improving the conditions which dictate when uploads should be displayed. This adds additional checks, reducing chances of errors when certain conditions (like the absence of an asset model or uploads) are met.