[explorer] Paste mlir text content into model-explorer

[madcampos]

Is your feature request related to a problem? Please describe

We want the ability to paste a copied text representing an mlir model into model-explorer.

Describe the solution you'd like

Add both an event listener for paste events, as well as a button to read the clipboard (for discoverability).

Then display the pasted model so users can review them and add the model for processing.

Describe alternatives you've considered

N/A

Additional context

When sharing models to other users, it is a common use case of sending the text itself instead of a file.

Another scenario is copying from the terminal or other forms of output without generating a file.