Double posts + Sync fixes

[RiccardoM]

Description

This PR fixes the problem that made so that the user viewed double posts when creating them. It also solves the sync process not working properly inside the version/0.5.0 branch. Closes #147.

Checklist

• [ ] Targeted PR against correct branch.
• [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• [ ] Wrote unit tests.
• [ ] Run flutter format.
• [ ] Updated the documentation.
• [ ] Added an entry to the CHANGELOG.md file.
• [ ] Re-reviewed Files changed in the Github PR explorer.

[codecov[bot]]

Codecov Report

Merging #149 into version/0.5.0 will increase coverage by 0.09%. The diff coverage is 80.00%.

@@                Coverage Diff                @@
##           version/0.5.0     #149      +/-   ##
=================================================
+ Coverage          63.67%   63.76%   +0.09%     
=================================================
  Files                277      277              
  Lines               7146     7161      +15     
=================================================
+ Hits                4550     4566      +16     
+ Misses              2596     2595       -1     

Impacted Files	Coverage Δ
lib/usecases/posts/usecase_delete_post.dart	80.00% <ø> (-3.34%)	:arrow_down:
lib/usecases/posts/usecase_update_post.dart	80.00% <ø> (-3.34%)	:arrow_down:
lib/entities/posts/post_status.dart	77.77% <28.57%> (+1.77%)	:arrow_up:
lib/ui/blocs/posts_list/posts_list_bloc.dart	58.43% <64.70%> (+1.29%)	:arrow_up:
lib/entities/posts/post.dart	86.59% <100.00%> (+1.37%)	:arrow_up:
lib/sources/posts/local/local_posts_source.dart	86.76% <100.00%> (ø)
lib/usecases/posts/usecase_create_post.dart	87.50% <100.00%> (+1.78%)	:arrow_up:
.../usecases/posts/usecase_manage_post_reactions.dart	80.00% <100.00%> (ø)
lib/usecases/posts/usecase_vote_poll.dart	87.50% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 50edc06...fe1de23. Read the comment docs.