Added config doc to verify screen (#21772)

Closes https://linear.app/ghost/issue/ENG-1729/check-what-happens-for-self-hosters-when-setting-up-a-new-site-without

- Added a link to the configs doc in case self hosters do not receive emails
- This is for the case when email is sent but not delivered.

ghost/admin/app/components/editor/modals/re-verify.hbs

@@ -55,6 +55,7 @@
             @useAccentColor={{true}}
             data-test-button="verify"
         />
+        <p class="main-notification">Not receiving the emails? <a href="https://ghost.org/docs/config/#mail" target="_blank" rel="noopener noreferrer">Learn more</a></p>
 
         {{#if (or this.flowErrors this.verifyData.validationMessage)}}
             <p class="response" data-test-error="verify">{{or this.flowErrors this.verifyData.validationMessage}}</p>

ghost/admin/app/templates/signin-verify.hbs

@@ -56,6 +56,8 @@
                     @type="submit"
                     @useAccentColor={{true}}
                     data-test-button="verify" />
+                
+                <p class="main-notification">Not receiving the emails? <a href="https://ghost.org/docs/config/#mail" target="_blank" rel="noopener noreferrer">Learn more</a></p>
             </form>
 
             {{#let (or this.flowErrors this.verifyData.validationMessage) as |error|}}