Project scoped stickiness
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Adds `projectScopedStickiness` flag to experimental.ts
Refactor Stickiness select for reusability
Modify FlexibleStrategy to respect the setting.
Modify EnvironmentVariantModal to respect the setting
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Signed-off-by: andreas-unleash <andreas@getunleash.ai>
* refactor: remove error class names from input error messages
* refactor: update error message test
* refactor: show constraint value length error earlier
