ExprRawName - fix an error from the toString method

[ShaneBeee]

Description

This PR aims to fix an NPE error when using this expression in a string, ie:

send "%minecraft name of player's tool%"

should return

[02:49:08 WARN]: [Skript] minecraft name of the tool of the player is already a text, so you should not put it in one (e.g. minecraft name of the tool of the player instead of "%minecraft name of the tool of the player%") (test.sk, line 6: send "%minecraft name of player's tool%"')

but instead its throwing an error.

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Target Minecraft Versions: any
Requirements: none
Related Issues: none

The base branch was changed.