Fix build metadata in workflow version causing semver parsing to fail

[PathogenDavid]

Not important for 2.8.3. The official release builds don't have build meadata so this doesn't affect them.

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Bonsai has randomly been telling me that it has "upgraded" workflows I literally just saved. I finally got annoyed enough to poke around to figure out why it thought my workflow was upgraded.

Turns out it was "upgrading" them because the version was null here, causing the check to always succeed:

bonsai/Bonsai.Editor/GraphModel/UpgradeHelper.cs

Lines 229 to 231 in 88a2412

	if (workflowElement is ExpressionBuilder builderElement && version < RemoveMemberSelectorPrefixVersion)
	{
	upgraded = true;

It was null because the parsing in SemanticVersion was not handling the build metadata. This change properly ignores it per the semver spec.

I considered adding a BuildMetadata property to SemanticVersion, but I felt it wasn't super valuable as this type is internal and is built around handling comparisons for the semver spec and the build metadata is completely ignored for those purposes.

This type currently has symmetry between equality operators and Equals/GetHashCode as well as comparison operators and CompareTo, but introducing this member properly should probably involve refactoring everything to break that symmetry. (Similar to how float.Equals is bitwise equality but float.operator== is IEEE-754 equality.)

[PathogenDavid]

I keep forgetting to note, but this was happening to me specifically because I have the .NET 8 SDK installed, which enables Source Link by default. Source Link adds the Git revision to the version strings by default (which is usually very useful.)

It also breaks the version display in the about box (because the version string is so long it wraps into an invisible region.)

I'll plan to just include this and similar changes in the release automation PR. Leaving this open as a draft as a reminder. (Gonçalo wanted this sooner rather than later so it got reopened and merged.)