Revert "code changes for SQL query built from user-controlled sources code ql issues"

This reverts commit 0d41d11.

Author: Akhileswara-Microsoft

App/kernel-memory/extensions/Postgres/Postgres/PostgresMemory.cs

@@ -232,18 +232,11 @@ private void Dispose(bool disposing)
     // Note: "_" is allowed in Postgres, but we normalize it to "-" for consistency with other DBs
     private static readonly Regex s_replaceIndexNameCharsRegex = new(@"[\s|\\|/|.|_|:]");
     private const string ValidSeparator = "-";
-    // Only allow 1-63 chars, start with a lowercase letter, then letters, digits, dashes, or underscores.
-    private static readonly Regex s_validIndexNameRegex = new(@"^[a-z][a-z0-9\-_]{0,62}$", RegexOptions.Compiled);
 
     private static string NormalizeIndexName(string index)
     {
         ArgumentNullExceptionEx.ThrowIfNullOrWhiteSpace(index, nameof(index), "The index name is empty");
         index = s_replaceIndexNameCharsRegex.Replace(index.Trim().ToLowerInvariant(), ValidSeparator);
-        // Enforce positive validation for safe Postgres identifier.
-        if (!s_validIndexNameRegex.IsMatch(index))
-        {
-            throw new ArgumentException($"Index name '{index}' is invalid. Must match regex: ^[a-z][a-z0-9\\-_]{{0,62}}$");
-        }
 
         PostgresSchema.ValidateTableName(index);