Incompatible files duplicates on redline package if its an attachments of two msg files

**Describe the bug in current situation**
If an incompatible file is part of two msg files, then it duplicates on Redline package

**Link bug to the User Story**

**Impact of this bug**
Describe the impact, i.e. what the impact is, and number of users impacted.

**Chance of Occurring (high/medium/low/very low)**

**Pre Conditions: which Env, any pre-requesites or assumptions to execute steps?**
test env

**Steps to Reproduce**
Steps to reproduce the behavior:
1. Go to records tab
2. Upload two msg files having common incompatible file
3. Then on the redline package, same incompatible file appears twice
4. See error

**Actual/ observed behaviour/ results**

**Expected behaviour**
A clear and concise description of what you expected to happen. Use the gherking language.

**Screenshots/ Visual Reference/ Source**
If applicable, add screenshots to help explain your problem. You an use screengrab.

Reproduce the issue from the records tab by uploading two MSG files with a shared incompatible attachment, then trace the redline package generation path. No source file or test is named in the issue, so first locate the code handling MSG attachments and incompatible files. Done means the shared incompatible file appears only once in the redline package and the behavior is covered by a regression test.

Written by the indexing model from the issue text.