For TypeScript compilation units that have the "strictFunctionTypes"
option enabled, an error would be produced for Ivy's definition fields
in declaration files in the case of inheritance across directives or
pipes.
This change loosens the definition types to allow for subtypes of the
defined type where necessary.
A test package that has the "strict" option enabled verifies that we
won't regress in environments where strict type checking is enabled.
Fixes#28079
PR Close#28634
06ec95f2ef