[Security Solution] Extend form lib with warnings

[maximpn]

Summary

Form lib should support warnings in a flexible way. Each validation should have an ability to return blocking and non blocking errors (a.k.a. warnings).

Details

Form lib implements warning functionality via non blocking validators. validations allows tospecify validation configuration with validator functions and extra parameters including isBlocking. Validators marked as isBlocking will produce non blocking validation errors a.k.a. warnings.

The problem with the supported approach is lack of flexibility and necessary API like one for getting only blocking or non blocking errors. Flexibility requirement comes from complex async validators producing blocking and non blocking validation errors. There is no way to use isBlocking configuration option to separate errors. Separating such validating functions in two would lead to sending two HTTP requests and performing another async operations twice.

On top of just having an ability to mark validation errors as non blocking via isBlocking: false configuration we require a way to return blocking and non blocking errors from a single validation function. It'd be possible by returning an error with isBlocking (or isWarning) flag along with message and code fields from a validator function. Attempts to reuse __isBlocking__ internal field lead to inconsistent behavior.

useFormWithWarn implemented in #202544 provides warnings (non blocking errors) implementatio on top of FormHook using validation error codes as a flexible way to determine whether an error is a blocking error or it's a warning. It provides little interface extension to simplify errors and warnings consumption

In some cases business logic requires implementing functionality to allow users perform an action despite non-critical validation errors a.k.a. warnings. Usually it's also required to inform users about warnings they got before proceeding for example via a modal.

Instead of spawning FormHook extensions we should have properly documented necessary warnings functionality in Form lib. It will help engineers building forms with better UX spending less efforts on reinventing warnings functionality.

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