Remove redundant Auspice build

Auspice has a prepare script that runs the build script automatically
after npm install. This means the explicit call to run the build script
is redundant and can be removed to improve build times.

Dockerfile

@@ -214,7 +214,7 @@ RUN curl -fsSL -o /final/bin/nextclade2 https://github.com/nextstrain/nextclade/
 # ⁴ https://github.com/mapbox/node-pre-gyp/blob/v1.0.10/lib/node-pre-gyp.js#L186
 WORKDIR /nextstrain/auspice
 RUN /builder-scripts/download-repo https://github.com/nextstrain/auspice release . \
- && npm update && npm install && npm run build && npm link
+ && npm update && npm install && npm link
 
 # Add NCBI Datasets command line tools for access to NCBI Datsets Virus Data Packages
 RUN curl -fsSL -o /final/bin/datasets https://ftp.ncbi.nlm.nih.gov/pub/datasets/command-line/v2/linux-${TARGETARCH}/datasets