Fixed the typing on ts 3.7+ (#3019)
Fixed the typing on ts 3.7+ (#3019)

TypeScript on [1] removed the null type on CSSStyleDeclaration.display.
As a result, our code violates the type checking when we do
`element.style.display = null`. Fixed it.

[1]:
https://github.com/microsoft/TypeScript/commit/29becf05012bfa7ba20d50b0d16813971e46b8a6

Co-authored-by: Martin Probst <54669547a225ff20cba8b75a4adca540eef25858@probst.io>
tensorflow/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard,tensorflow/tensorboard