[model_card] Add meta + fix link to image

(hotlinking to image works on GitHub but not on external sites)

cc @bashartalafha

model_cards/bashar-talafha/multi-dialect-bert-base-arabic/README.md

+---
+language: arabic
+thumbnail: https://raw.githubusercontent.com/mawdoo3/Multi-dialect-Arabic-BERT/master/multidialct_arabic_bert.png
+datasets:
+- nadi
+---
 # Multi-dialect-Arabic-BERT
 This is a repository of Multi-dialect Arabic BERT model.
 
@@ -5,7 +11,7 @@ By [Mawdoo3-AI](https://ai.mawdoo3.com/).
 
 <p align="center">
     <br>
-    <img src="https://github.com/mawdoo3/Multi-dialect-Arabic-BERT/blob/master/multidialct_arabic_bert.png" alt="Background reference: http://www.qfi.org/wp-content/uploads/2018/02/Qfi_Infographic_Mother-Language_Final.pdf" width="500"/>
+    <img src="https://raw.githubusercontent.com/mawdoo3/Multi-dialect-Arabic-BERT/master/multidialct_arabic_bert.png" alt="Background reference: http://www.qfi.org/wp-content/uploads/2018/02/Qfi_Infographic_Mother-Language_Final.pdf" width="500"/>
     <br>
 <p>