Remove safe navigation rubocop rule

[adfoster-r7]

In certain scenarios it's possible for this Rubocop rule to produce broken Ruby code.

I believe rubocop is only meant to perform this transform for specific methods, but it doesn't appear to work:

  AllowedMethods:
    - present?
    - blank?
    - presence
    - try
    - try!

Let's disable the rule for now, and I've raised an issue with Rubocop

Full context: #13291 (comment)
Rubocop issue: rubocop/rubocop#7914

[gwillcox-r7]

Seems to be working as expected:

$ git log
commit 81f0607ac3b1366abfb18081013def12a8352578 (HEAD, upstream/pr/13347)
Author: adfoster-r7 <adfoster-r7@github>
Date:   Mon Apr 27 18:04:33 2020 +0100

    Remove safe navigation rubocop rule

commit fc164e0c098456bcc65d3f2605a0580ff0e2965e (upstream/master, origin/master, origin/HEAD, upstream-master, master)
Author: Metasploit Bot <metasploit@rapid7.com>
Date:   Mon Apr 27 06:16:47 2020 -0500

    automatic module_metadata_base.json update

commit af239303d206ae2fb3c78c55244c662d7c463f1e
Merge: 64c04464e0 090cf259ee
Author: cdelafuente-r7 <cdelafuente-r7@github>
Date:   Mon Apr 27 13:05:38 2020 +0200

    Land #13257, .NET Deserialization Library Improvements

commit 64c04464e0aa9e4bb242232471a63c88106e39c2
Author: Metasploit Bot <metasploit@rapid7.com>
Date:   Sat Apr 25 15:48:58 2020 -0500

    automatic module_metadata_base.json update

$ rubocop -c .rubocop.yml modules/exploits/example_linux_priv_esc.rb 
.rubocop.yml: Metrics/LineLength has the wrong namespace - should be Layout
/*censored*/metasploit-framework/.rubocop.yml: Warning: no department given for Documentation.
Inspecting 1 file
.

1 file inspected, no offenses detected
$ 

Going to go ahead and merge this as rubocop/rubocop#7914 and #13291 (comment) clearly show that several people have tested this issue and confirmed that it is a bug in RuboCop.