Fix dialog message

[ssvine]

This PR fixes this issues:

• In function UnicodeString WrapText(const UnicodeString & Line, int32_t MaxWidth) the MaxWidth param is not max width, actual max width is always less than that.
• DialogMessage has edge cases when buttons go out of borders
• A long text line that should fit the whole client area width of DialogMessage has inconsistent spacing: 1 space on the left (correct) and 2 spaces on the right (should be 1 space):
  || Long text || - before fix
  || Long text || - after fix

An example of buttons going out of borders:

An example of fixed dialog, that also shows correct spacing and text wrapping:

@michaellukashov, You should also fix test1 function in the file tests/testnetbox_02.cpp in far3-dev-tests branch:

    REQUIRE_EQUAL(3, MessageLines.GetCount());
    REQUIRE_EQUAL(L"long long long long", MessageLines.GetString(0));
    REQUIRE_EQUAL("long long long long", W2MB(MessageLines.GetString(1).c_str()));
    REQUIRE_EQUAL("long text", W2MB(MessageLines.GetString(2).c_str()));

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

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