Harmonize SDK

[Aschen]

What does this PR do?

When harmonizing the documentation for the SDJ JS 6, I noticed a few things that deserve to be corrected

• The method auth:updateSelf was returning a promise that resolve to a JSON object.
  ➡️ Change the value resolved by the promise to a User object, like the getCurrentUser method

• The method collection:updateSpecification return an object containing the index and the collection where the specifications were updated.
  ➡️ Return only the updated specifications

How should this be manually tested?

• Step 1 : Run tests

[codecov-io]

Codecov Report

Merging #326 into 6-dev will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##            6-dev     #326   +/-   ##
=======================================
  Coverage   97.28%   97.28%           
=======================================
  Files          28       28           
  Lines        1401     1401           
=======================================
  Hits         1363     1363           
  Misses         38       38

Impacted Files	Coverage Δ
src/controllers/bulk.js	100% <100%> (ø)	⬆️
src/controllers/auth.js	92.5% <100%> (ø)	⬆️
src/controllers/collection.js	94.87% <100%> (ø)	⬆️

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