refactor(@schematics/angular): remove unneeded speed-measure-plugin output from gitignore

With the removal of the `speed-measure-plugin` from the build system, the file no longer needs to be ignored by git in new projects.

Author: clydin

packages/schematics/angular/workspace/files/__dot__gitignore.template

@@ -12,7 +12,6 @@
 
 # profiling files
 chrome-profiler-events*.json
-speed-measure-plugin*.json
 
 # IDEs and editors
 /.idea