Prevent browser from crashing to quickly

[binerdy]

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] The commit message follows our guidelines: https://github.com/CirclonGroup/angular-tree-component/blob/master/CONTRIBUTING.md#commit-message-guidelines

PR Type

What kind of change does this PR introduce?

• [x] Bugfix / Performance

What is the current behavior?

Browser crashes after trying to expand all nodes flagged with isExpanded, if the tree is large enough. This PR doesn't solve it but it extends the current limit.

Closes #923