Fix branch merge when merging multiple times

In intermediate / Advanced mode

• As User 1
• Create a "YellowBranding" branch
• Create a "TotoBranding" with yellow color
• Save WIP, commit & push
• Create a "PinkBranding" branch
• Create a "TotoBranding" with pink color on the same items (we're trying to create a conflict here)
• Save WIP, commit & push
• Checkout "master" branch
• Merge "YellowBranding" into master
• Pull changes
• Merge "PinkBranding" into master
• Pull changes, solve conflict by choosing the local files
  => TotoBranding is currently yellow

• Merge "PinkBranding" into master
  => Solve conflict by choosing remote files
  => Nothing can be pulled, TotoBranding is still yellow
  => When reloading the project, TotoBranding is still yellow

• As User 2
  => Log in
  => Changes can be pulled, when pulling TotoBranding is pink

• As User 1
• Merge "PinkBranding" one more time into master
• During conflict, chooses local files (yellow branding)
  => User 2 has nothing to pull anymore and still sees branding as pink.