perf: significantly reduce form-state response size by up to 2x

[jacobsfletch]

This significantly optimizes the form-state response, reducing its size by up to more than 2x. This has rolling effects on initial page size as well, where the initial state for the entire form is sent through the request. To achieve this, we do the following:

• Remove $undefined strings that are potentially attached to properties like value, initialValue, fieldSchema, etc.
• Remove unnecessary properties like empty errorPaths arrays and empty customComponents objects, which only need to exist if used
• Remove unnecessary properties like valid, passesCondition, etc. which only need to be returned if explicitly false
• Remove unused properties like isSidebar, which simply don't need to exist at all, as they can be easily calculated during render

For backward compatibility, some of these changes are behind a temporary experimental.optimized flag.

Results

The following results were gathered by booting up each test suite listed below using the existing seed data, navigating to a document in the relevant collection, then typing a single letter into the noted field in order to invoke new form-state. The result is then saved to the file system for comparison.

Test Suite	Collection	Field	Before	After
field-perf	blocks-collection	layout.0.field1	177 kB	98 kB
fields	array-fields	items.0.text	8 kB	4 kB
fields	block-fields	blocks.0.richText	28 kB	22 kB