[Bug]: Gnatformat engine always used even if useGnatformat is false

[JHag6694]

Environment

• OS and Version: Windows 11
• IDE Version: VS Code 1.106.3
• Ada & SPARK Extension Version: 2026.0.202510141

Bug Summary and Reproducer

Bug Summary: Gnatformat engine always used even if useGnatformat is false

Steps to reproduce:

• Set formatter as legacy gnatpp engine (with .als.json or in the workspace setting file)
• Set a different indentation parameter in package Pretty_Printer and Format (ex : indentation = 3 vs. 2)
• Trigger format document

Expected behavior:
Ada source code should be reformatted using Pretty_Printer indentation value
But Ada source code is reformatted using Print indentation value
NB : Behavior is different - and correct - if previous version 26.0.202507021 is installed

.als.json

{
    "projectFile": "hello.gpr",
    "scenarioVariables": {},
    "onTypeFormatting": {
        "indentOnly": true
    },
    "useGnatformat": false
}

hello.gpr

-- TOP OF FILE
project Hello is
   for Object_Dir use "obj";
   for Main use ("hello.adb");

   package Compiler is
      for Default_Switches ("Ada") use ("-g");
   end Compiler;

   package Pretty_Printer is
      for Default_Switches ("ada") use
        (
         "--name-mixed-case",
         "--no-end-id",
         "--source-line-breaks",
         "--indentation=3"
        );
   end Pretty_Printer;

   package Format is
      for Indentation ("Ada") use "2";
   end Format;

end Hello;

Configuration and Logs

no compiler installed
tasks.json empty

Other VS Code Extensions

None

Additional context

None