Adding changes to reduce false positives seen by customers

[SharmaAkash1]

The changes made in the script are as follows:

1. For Cve26858 we only show the error if the path in the error message “Download failed and temporary file needs to be removed” is invalid (does not start with C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\OAB)
2. For set-virtual directory we throw an error only if the url is invalid
3. For the get-suspicious files we only show those if one of the 4 vulnerabilities (Cve26855 Or Cve26857 or Cve26858 or Cve27065 ) is found.
   This was done because even customers who did not have any vulnerabilities were alerted due to the presence of some zip files that they had created in their system.
   These false positives lead to a lot of confusion and the uneasiness for the customers.
4. We also show an additional error message regarding web shells if we find logs of successful reset-virtualdirectory hits (having a bad anchor mailbox object) in the httpsproxy folder.

[bill-long]

Please run .build\CodeFormatter.ps1 -Save and then correct the PSScriptAnalyzer issues manually:

RuleName                              Severity    ScriptName          Line Message
--------                              --------    ----------          ---- -------
PSAvoidTrailingWhitespace             Information Test-ProxyLogon.ps1 172  Line has trailing whitespace
PSAvoidTrailingWhitespace             Information Test-ProxyLogon.ps1 194  Line has trailing whitespace
PSAvoidTrailingWhitespace             Information Test-ProxyLogon.ps1 210  Line has trailing whitespace
PSAvoidTrailingWhitespace             Information Test-ProxyLogon.ps1 219  Line has trailing whitespace
PSAvoidTrailingWhitespace             Information Test-ProxyLogon.ps1 228  Line has trailing whitespace
PSAvoidTrailingWhitespace             Information Test-ProxyLogon.ps1 229  Line has trailing whitespace
PSPossibleIncorrectComparisonWithNull Warning     Test-ProxyLogon.ps1 186  $null should be on the left side of
                                                                           equality comparisons.
PSPossibleIncorrectComparisonWithNull Warning     Test-ProxyLogon.ps1 186  $null should be on the left side of
                                                                           equality comparisons.
PSUseDeclaredVarsMoreThanAssignments  Warning     Test-ProxyLogon.ps1 225  The variable 'FoundMaliciousResetVDir' is
                                                                           assigned but never used.