[chore] migration of plugin-store (#27506)

Plugin store is gradually migrated from:
- https://plugins-store.test.mattermost.com
to
- https://plugins.releases.mattermost.com

We reflect that change here

Note: Currently both CDN's are working as expected, to facilitate the mgiration. Upon succesfull migration, https://plugins-store.test.mattermost.com will be decomissioned

server/build/release.mk

@@ -145,8 +145,8 @@ fetch-prepackaged-plugins:
 	mkdir -p tmpprepackaged
 	@echo "Downloading prepackaged plugins ... "
 	@cd tmpprepackaged && for plugin_package in $(PLUGIN_PACKAGES) ; do \
-		curl -f -O -L https://plugins-store.test.mattermost.com/release/$$plugin_package-$(PLUGIN_ARCH).tar.gz; \
-		curl -f -O -L https://plugins-store.test.mattermost.com/release/$$plugin_package-$(PLUGIN_ARCH).tar.gz.sig; \
+		curl -f -O -L https://plugins.releases.mattermost.com/release/$$plugin_package-$(PLUGIN_ARCH).tar.gz; \
+		curl -f -O -L https://plugins.releases.mattermost.com/release/$$plugin_package-$(PLUGIN_ARCH).tar.gz.sig; \
 	done
 	@echo "Done"