Advance master to 2.0.2-preview (#4741)

# Description

#4740 makes `release/2.0` the stable `2.0.1` release. This PR moves
`master` from `2.0.1-preview.{height}` to `2.0.2-preview.{height}`, so
its builds sort above the `2.0.1` release and stay on the preview
channel.

- **`version.json`**: `"version"` `2.0.1-preview.{height}` →
`2.0.2-preview.{height}`. `versionHeightOffset` stays `0`.
- **`preview-version.props`**: unchanged. `PreviewPackageBuildNumber`
only applies when the root version is stable, so it has no effect on
`master`.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

version.json

@@ -1,6 +1,6 @@
 {
   "$schema": "https://raw.githubusercontent.com/AArnott/Nerdbank.GitVersioning/master/src/NerdBank.GitVersioning/version.schema.json",
-  "version": "2.0.1-preview.{height}",
+  "version": "2.0.2-preview.{height}",
   "versionHeightOffset": 0,
   "nugetPackageVersion": {
     "semVer": 2