IntelFsp2Pkg/Tools/ConfigEditor: Fixed YAML data overwrite issue

[yunhsiax]

Problem Description:
The condition if force or act_cfg['value'] == '' in _set_field_value() caused valid YAML values
to be wrongly overwritten with binary data.
Since force=True made the condition always true, correct YAML entries like "0xFE02C000" were replaced
by binary values such as "0x01010101", leading to corrupted configurations and incorrect FSP settings.

Solution Implementation:
The condition was updated to if act_cfg['value'] == '', removing the force dependency.
This ensures binary data is used only when the YAML value is empty,
preserving valid configurations and preventing overwrites.

[tianocore-pr-automation]

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[tedkuo1]

This should be a right solution for the issue.