fix(sql): withhold the JSON parser's message from the probe's red result (Driver.Sql-009)

SqlDriverProbe surfaced 'Config JSON is invalid: ' + ex.Message, where
SqlDriverBrowser.ParseDocument deliberately withholds the identical message
because the malformed text may itself carry a connection string. The two read
the same blob shape - the AdminUI Sql picker composes a document with a
top-level connectionString literal - so a malformed paste reaches both. The
probe now reports the failure class only, matching the browser.

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Sql/SqlDriverProbe.cs

@@ -19,7 +19,10 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.Sql;
 ///     timeout, a cancellation — becomes a red <see cref="DriverProbeResult"/>, so the AdminUI has nothing to
 ///     catch.</para>
 ///     <para><b>The resolved connection string never reaches the result message.</b> A red result names the
-///     failure class, never the string — the same credential discipline the factory and the driver keep.</para>
+///     failure class, never the string — the same credential discipline the factory and the driver keep.
+///     That includes the JSON parser: a malformed config is reported as a class, with the parser's own
+///     message withheld exactly as <c>SqlDriverBrowser.ParseDocument</c> withholds it, because the malformed
+///     text may itself be a pasted connection string.</para>
 /// </summary>
 public sealed class SqlDriverProbe : IDriverProbe
 {
@@ -80,7 +83,16 @@ public sealed class SqlDriverProbe : IDriverProbe
         }
         catch (Exception ex) when (ex is System.Text.Json.JsonException or ArgumentNullException)
         {
-            return new DriverProbeResult(false, $"Config JSON is invalid: {ex.Message}", null);
+            // The parser's message is WITHHELD, matching SqlDriverBrowser.ParseDocument. Nothing has been
+            // extracted at this point, so there is no known secret to redact the message against — and the
+            // blob both types read is the one the AdminUI Sql picker composes, which carries a top-level
+            // `connectionString` literal. A malformed paste is therefore exactly the text that reaches here,
+            // and System.Text.Json quotes the offending token and states the JSON path and byte position.
+            return new DriverProbeResult(
+                false,
+                "Config JSON is not valid JSON. (The parser's message is withheld because the malformed "
+                + "text may carry a connection string.)",
+                null);
         }
 
         if (dto is null)