Remove inline style not joining siblings

[Garry Yao]

Reproducing Procedures

1. Open any of the sample page;
2. Load the following content in editor;

   <p>
   	Some sample text</p>
   

3. Select 'Some sample' and apply the 'Bold' style;
4. Select 'sample text' and apply the 'Italic' style;
5. Select 'sample' and remove the 'Bold' style;
6. Swtich to Source mode and check the output.
   • Actual Result:

     <p><strong>This </strong><em>is</em><em> some</em></p>
     

   • Expected Result:

     <p><strong>This </strong><em>is some</em></p>