Revert "Forms: add combobox for phone country selector"

[CGastrell]

Reverts #45120

[github-actions]

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[github-actions]

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[jp-launch-control]

Code Coverage Summary

Coverage changed in 6 files. Only the first 5 are listed here.

File	Coverage	Δ%	Δ Uncovered
projects/packages/forms/src/blocks/contact-form/class-contact-form-block.php	384/589 (65.20%)	-0.06%	0 💚
projects/packages/forms/src/contact-form/class-contact-form-field.php	805/1395 (57.71%)	-6.84%	0 💚
projects/packages/forms/src/contact-form/class-contact-form-plugin.php	412/1291 (31.91%)	0.05%	-2 💚
projects/packages/forms/src/blocks/field-telephone/edit.js	0/22 (0.00%)	0.00%	-3 💚
projects/packages/forms/src/blocks/input-phone/edit.js	0/16 (0.00%)	0.00%	-13 💚

Full summary · PHP report · JS report

_{Coverage check overridden by Coverage tests to be added later Use to ignore the Code coverage requirement check when tests will be added in a follow-up PR .}

[CGastrell]

We succeeded by busting cache #45137 and will follow up with #45138 for a more robust/proper approach