Pin properties dialog complains with error popup if the pin is not on 50 mil grid

The warning for "pin hard to connect if not on 50mil grid" is generated by the pin properties dialog even if the coordinates are not changed by it (for example if one tries to edit an already off grid pin)

See https://forum.kicad.info/t/disable-grid-warning-in-symbol-editor/23423/

Description

Steps to reproduce

1. open any symbol
2. move a pin for example by 25mil (using the move command)
3. open the pin properties of that moved pin and change nothing in it
4. press ok and note that the warning pops up

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Expected behaviour: the warning only pops up if the user changes the pin coordinates. Bonus points if the warning either depends on the current grid setting or is at least configurable

KiCad Version

Application: KiCad
Version: 5.1.5-1.fc30, release build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.65.3 OpenSSL/1.1.1g-fips zlib/1.2.11 brotli/1.0.7 libidn2/2.3.0 libpsl/0.20.2 (+libidn2/2.0.5) libssh/0.9.3/openssl/zlib nghttp2/1.40.0
Platform: Linux 5.6.13-100.fc30.x86_64 x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 3.24
    Boost: 1.69.0
    OpenCASCADE Technology: 7.4.0
    Curl: 7.65.3
    Compiler: GCC 9.2.1 with C++ ABI 1013

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=ON
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=OFF
    KICAD_USE_OCC=ON
    KICAD_SPICE=ON