Update code snippet format in the OAuth docs

[horeaporutiu]

Summary

The installation object was not rendering properly. Change the code snippet to be of type javascript instead of json.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #1318 (3ac5b2d) into main (66ec23c) will not change coverage.
The diff coverage is n/a.

❗ Current head 3ac5b2d differs from pull request most recent head 7f50aec. Consider uploading reports for the commit 7f50aec to get more accurate results

@@           Coverage Diff           @@
##             main    #1318   +/-   ##
=======================================
  Coverage   72.88%   72.88%           
=======================================
  Files          17       17           
  Lines        1479     1479           
  Branches      442      442           
=======================================
  Hits         1078     1078           
  Misses        311      311           
  Partials       90       90           

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