Update Helix Toolkit from 2.11 to 2.15

[saintentropy]

Purpose

This PR is to update the Helix Toolkit (and by association the Cyotek.Drawing.BitmapFont dependency) from version 2.11 to version 2.15. The purpose of this PR is to address a memory optimization related to the #11395 PR (Generating a single render package per node). Specifically the helix-toolkit/helix-toolkit#1494 PR modifies the behavior of the VertexArrayBuffer which was being retained in memory as a sparse array based on the largest size mesh to be rendered in the session. In 2.15 this buffer is not pinned to the largest allocation size in session.

As a point of interest. This Helix PR fix was triggered due to the issue filed by @aparajit-pratap. helix-toolkit/helix-toolkit#1449

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated

Reviewers

@aparajit-pratap @mmisol

FYIs

@mjkkirschner

[mjkkirschner]

I must be misunderstanding that PR - because it still looks like the behavior is to create a buffer(vertexCount) ?

Also since the default for isTransient is false, we're not taking advantage of the buffer being cleared - and if we were, then hit testing would be broken it seems.

[saintentropy]

@mjkkirschner for our purposes the new ThreadBufferManager is what affects us. Here are the relevant changes to the MeshBufferModel and LineBufferModel:

and

The original local vertexArrayBuffer was always retained and would just keeping getting larger based on the largest array of the session. Now per their documentation -> per their notes /// If requested size is larger than this value, buffer will be temporary instead of being retained for reuse.

[saintentropy]

The isTransient optimization can be looked at in the future but not related to the memory issue we were addressing

[mjkkirschner]

It looks good to me, but it's probably good to run the view comparison tests.

[saintentropy]

Image comparisons are pass @mjkkirschner @aparajit-pratap