Preheader (Preview text) is being appended with the actual contents of the email (body text)

### Expected Behaviour

When Preheader text is less than 90 characters long it should not be appended by email body content but rather show empty space.

### Actual Behaviour

When Preheader text is less than 90 characters long it is being appended by email body content rather than showing empty space.

### Reproduce Scenario (including but not limited to)

#### Steps to Reproduce

Use preheader text which is less than 90 characters long and run tests via litmus (see first impressions section) or Campaign (you will see additional text after preview text in your email client)

#### Platform and Version

AEM 6.5.13
Core Email component s - 0.20.0

#### Sample Code that illustrates the problem

#### Logs taken while reproducing problem

### Screenshot from Litmus

Start by reproducing the issue with preheader text under 90 characters in AEM 6.5.13 using Core Email Components 0.20.0, then compare the generated email in Litmus or Campaign. Done means the preview text is followed by empty space rather than appended email body content.

Written by the indexing model from the issue text.