Remove deprecated info on Theme's doc

[lonyele]

From storybook v5, name and url are deprecated and moved to theme object with brandTitle, brandUrl. It is working now since name, url are backward compatibility until 6.0. It would be better if it is removed from the doc for less confusion.

What I did

I removed name key/value on arguments of addParameter()

How to test

• Is this testable with Jest or Chromatic screenshots? NO
• Does this need a new example in the kitchen sink apps? NO
• Does this need an update to the documentation? YES

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[github-actions]

	Fails
🚫	PR is not labeled with one of: ["cleanup","doc-dependencies:update","BREAKING CHANGE","feature request","bug","documentation","maintenance","dependencies:update","dependencies","other"]

Generated by 🚫 dangerJS against 75b562d

[codecov]

Codecov Report

Merging #6446 into next will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             next    #6446   +/-   ##
=======================================
  Coverage   41.04%   41.04%           
=======================================
  Files         613      613           
  Lines        8454     8454           
  Branches      378      378           
=======================================
  Hits         3470     3470           
  Misses       4929     4929           
  Partials       55       55

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