System.DirectoryServices.Protocols.SearchRequest Filter does not allow unnecessary space-escapes unlike on Windows #127175

Description

When writing an ldap filter with a space in it, a leading backslash is needed if the space is at the beginning or end of the entry. For simplicity, it's common practice to backslash-escape any space in an LDAP query. This is not permitted on Linux, but is on Windows.

Invoking through powershell:

$conn.SendRequest([System.DirectoryServices.Protocols.SearchRequest]::new(
    "DC=samdom,DC=example,DC=com",
    "(&(objectClass=organizationalUnit)(distinguishedName=OU=Domain\ Controllers,DC=samdom,DC=example,DC=com))",
    "subtree",
    "*"
))

is permitted on Windows but fails on Linux.

Note that I have not tested space-at-the-beginning-and-end behaviour, only internal spaces because that's what comes up more frequently.

Reproduction Steps

using the following docker-compose.yml to create an LDAP server on localhost:

services:
  smblds:
    environment:
    - INSECURE_LDAP=true
    image: 'smblds/smblds:latest'
    ports:
      - 389:389
      - 636:636

Invoke the following (using pwsh to demonstrate).

Add-Type -path $assemblyPath

# default credentials for `smblds` for testing purposes.
$credential = [Management.Automation.PSCredential]::new('SAMDOM\Administrator', (ConvertTo-SecureString 'Passw0rd' -AsPlainText -Force))
$identifier = [System.DirectoryServices.Protocols.LdapDirectoryIdentifier]::new('localhost', 389)
$conn = [System.DirectoryServices.Protocols.LDAPConnection]::new($identifier, $credential, 'Basic')
$result = $null
$conn.SendRequest([System.DirectoryServices.Protocols.SearchRequest]::new(
    "DC=samdom,DC=example,DC=com",
    "(&(objectClass=organizationalUnit)(distinguishedName=OU=Domain\ Controllers,DC=samdom,DC=example,DC=com))",
    "subtree",
    "*"
))

Works fine in pwsh (which uses netcore) and PS5.1 (which uses framework) but fails on linux.

Expected behavior

Return OrganizationalUnit searchresponse.

Actual behavior

MethodInvocationException: Exception calling "SendRequest" with "1" argument(s): "The search filter is invalid."

Regression?

No response

Known Workarounds

No response

Configuration

Ubuntu 22.04, .NET 8.0, x64

Other information

No response