Support field type conversion for Multi Choice fields

[XingY]

Rationale

Instead of two separate data types, this PR modifies TextChoice so multi choice is no longer an explicit option in designer, but rather, can be enabled to checking a "multi" check box after selecting text choice option.

Related Pull Requests

• Update Array filter multi-value delimiter to ';' to match IN/NOT IN filter types labkey-api-js#205
• Support field type conversion for Multi Choice fields #1927
• Support field type conversion for Multi Choice fields platform#7356
• https://github.com/LabKey/limsModules/pull/1940

Changes

• Updates the Text Choice options UI to add an “Allow multiple selections” toggle, multi-choice-specific edit restrictions, and improved confirmation messaging/tests for data-type changes involving text/multi-choice.
• Make multi-choice behaves as an internal variant of Text Choice rather than a separate visible type in data type dropdown
• Enhances updateDataType and text choice usage counting to correctly handle conversions between string, Text Choice, and Multi Choice fields, clearing validators/flags and tracking multi-value usage where appropriate.