[FIX] digest: tips will be displayed properly

Currenly in the digest when you send the template, tips are not being seen.

The reason for this is, we are getting tips from the context but we dont have it in the context.
Instead, we are fetching the tips by calling the compute_tips method and assigning it to 'tips'.

Hence, this commit will remove the usage of context to get the tips as we are getting it
from the method and not from the context.

Task ID: #1918364

addons/digest/data/digest_template_data.xml

@@ -115,7 +115,7 @@
                 <table style="width: 100%; max-width: 600px; margin-top: 5px; border: 1px solid #e7e7e7;">
                     <tr>
                         <td style="border-collapse: collapse; background-color: #ffffff; line-height: 21px; padding: 0px 20px;"><br/>
-                            <div style="color: #3d466e; line-height: 23px;">${ctx['tip_description']|safe}</div>
+                            <div style="color: #3d466e; line-height: 23px;">${tips | safe}</div>
                         </td>
                     </tr>
                 </table>