e2e: Ensure we build the grafana binary when starting up the playwright server (#108992)

* ensure we build the grafana binary as part of the playwright server startup

* only build if binary isn't there

* add comments

* handle building the binary in the start-server script

scripts/grafana-server/start-server

@@ -22,6 +22,13 @@ fi
 
 echo starting server
 
+# air now deletes the binary, so we check if we need to build it before trying to start the server
+# see https://github.com/air-verse/air/issues/525
+# if this gets resolved, we could remove the go build and rely on the binary being present as before
+if [[ ! -f ./bin/grafana ]]; then
+  make GO_BUILD_DEV=1 build-go-fast
+fi
+
 cp -r ./bin $RUNDIR
 cp -r ./tools $RUNDIR
 ln -s $(realpath ./public) $RUNDIR