The panel currently exposes a `disposables` protected member. In order to catch possible leaks of disposables, we should extend `Disposable` instead

`lifecycle/Disposable` includes some important fixes that can help catch common programming mistakes

The dom.d.ts types changed to not allow null on the outline styles. I believe that setting this to empty string should be equivalent

Fixes #74710

* Adding setting to control the background color for the active tab in an unfocused editor group

* Adding style fixes for unfocused container group when shrink mode is enabled in tab sizing

* fine-graining the selectors to correctly address the unfocused active tab

* move tab unfocused bg color and use current active background values as defaults

* extracting CSS selectors into a generator function to collect common code and reduce redundancies

Fixes #74295

This is a partial revert of 4929acf9 . I'm having trouble indentifying which specific change caused this to break so I'm reverting both of these methods

Part of #74250

- Extend `Disposable` in classes where it makes sense
- Use `DisposableStore` for lists of disposables
- Make `combinedDisposable` take arguments instead of an array (so that you can't pass in an array and then modify the array after the fact)

Fixes #74242

Our current usage of dispoable arrays can leak disposables (see #74242 for details). This change introduces a new class called `DisposableStore` that can be used mostly as a drop in replacement for an array of disposables but will not leak disposbles if it is disposed

`DisposableStore` was extracted from the existing `Dispoable` class, which already implements this pattern. However `Disposable` is intended to be used as a base class while `DispoableStore` is a value class.

In addition, this change hides the `toDispose` / `_toDipose` members of `Disposable` as direct write access to the disposable array also allows for leaks (and breaks encapsulation)

Fixes #74191

Instead of using a base64 encoded data uri to display images, use the fileService to read Buffer, convert this to a Blob, and display the blob

more consistency