fix: fix Field.data for LegacyGrpcServer

[PProfizi]

A script using only a LegacyGrpcServer would raise an AttributeError in Field._get_data when trying to create a DPFVectorDouble.
This error type was no longer caught in #2141

[github-actions]

Some tests with 'continue-on-error: true' have failed:

• PyDPF-Post API tests on ubuntu-latest

• PyDPF-Post docstring tests on windows-latest

  Created by continue-on-error-comment

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.36%. Comparing base (8d518f6) to head (2c9ef47).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2668      +/-   ##
==========================================
+ Coverage   84.26%   84.36%   +0.10%     
==========================================
  Files          92       92              
  Lines       10858    10858              
==========================================
+ Hits         9149     9160      +11     
+ Misses       1709     1698      -11     

[PProfizi]

Waiting for #2669 to have the configuration of the issue covered in the CI and verify that this fixes it.

[PProfizi]

Fix confirmed.
The fix actually fixes other legacy gRPC tests which were depending on having DPFCLientAPI.dll having been loaded by a previous start of an InProcess server. (such as test_operator_coordinate_system_rst)