Remove request trial form from docs

[khanhtc1202]

What this PR does / why we need it:

Remove trial form link from docs, we want users to use the tutorial instead.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 22.80%. Comparing base (c9861c7) to head (7331de0).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5145   +/-   ##
=======================================
  Coverage   22.80%   22.80%           
=======================================
  Files         412      412           
  Lines       43827    43827           
=======================================
  Hits         9996     9996           
  Misses      33044    33044           
  Partials      787      787           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.