[Canvas] Kibana not starting if reporting is disabled

[fdeschamps]

Kibana version: 6.5.0

Elasticsearch version: 6.5.0

Original install method (e.g. download page, yum, from source, etc.): ubuntu package

Describe the bug: Kibana not starting if reporting plugin is disabled

Steps to reproduce:

1. Put xpack.reporting.enabled: false in kibana configuration
2. Start Kibana
3. Kibana stop while optimizing

Provide logs and/or server output (if relevant):

{"type":"log","@timestamp":"2018-11-15T15:08:51Z","tags":["info","optimize"],"pid":29223,"message":"Optimizing and caching bundles for ml, stateSessionStorageRedirect, status_page, timelion, graph, monitoring, space_selector, login, logout, dashboardViewer, apm, canvas, infra and kibana. This may take a few minutes"}
{"type":"error","@timestamp":"2018-11-15T15:11:58Z","tags":["fatal","root"],"pid":29223,"level":"fatal","error":{"message":"Optimizations failure.\n   8001 modules\n    \n    \u001b[1m\u001b[31mERROR in /usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export/index.js\n    Module not found: Error: Can't resolve 'plugins/reporting/lib/job_completion_notifications' in '/usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export'\u001b[39m\u001b[22m\n","name":"Error","stack":"Error: Optimizations failure.\n   8001 modules\n    \n    \u001b[1m\u001b[31mERROR in /usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export/index.js\n    Module not found: Error: Can't resolve 'plugins/reporting/lib/job_completion_notifications' in '/usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export'\u001b[39m\u001b[22m\n\n    at FsOptimizer.failedStatsToError (/usr/share/kibana/src/optimize/base_optimizer.js:379:27)\n    at compiler.run (/usr/share/kibana/src/optimize/fs_optimizer.js:47:26)\n    at onCompiled (/usr/share/kibana/node_modules/webpack/lib/Compiler.js:241:12)\n    at applyPluginsAsync.err (/usr/share/kibana/node_modules/webpack/lib/Compiler.js:514:14)\n    at next (/usr/share/kibana/node_modules/tapable/lib/Tapable.js:202:11)\n    at Compiler.<anonymous> (/usr/share/kibana/node_modules/webpack/lib/CachePlugin.js:78:5)\n    at Compiler.applyPluginsAsyncSeries (/usr/share/kibana/node_modules/tapable/lib/Tapable.js:206:13)\n    at compilation.seal.err (/usr/share/kibana/node_modules/webpack/lib/Compiler.js:511:11)\n    at Compilation.applyPluginsAsyncSeries (/usr/share/kibana/node_modules/tapable/lib/Tapable.js:195:46)\n    at self.applyPluginsAsync.err (/usr/share/kibana/node_modules/webpack/lib/Compilation.js:671:19)\n    at Compilation.applyPluginsAsyncSeries (/usr/share/kibana/node_modules/tapable/lib/Tapable.js:195:46)\n    at self.applyPluginsAsync.err (/usr/share/kibana/node_modules/webpack/lib/Compilation.js:662:11)\n    at next (/usr/share/kibana/node_modules/tapable/lib/Tapable.js:202:11)\n    at /usr/share/kibana/node_modules/uglifyjs-webpack-plugin/dist/index.js:282:11\n    at step (/usr/share/kibana/node_modules/uglifyjs-webpack-plugin/dist/uglify/index.js:90:11)\n    at done (/usr/share/kibana/node_modules/uglifyjs-webpack-plugin/dist/uglify/index.js:99:22)\n    at /usr/share/kibana/node_modules/uglifyjs-webpack-plugin/dist/uglify/index.js:105:15\n    at /usr/share/kibana/node_modules/worker-farm/lib/farm.js:191:19\n    at _combinedTickCallback (internal/process/next_tick.js:131:7)\n    at process._tickCallback (internal/process/next_tick.js:180:9)"},"message":"Optimizations failure.\n   8001 modules\n    \n    ERROR in /usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export/index.js\n    Module not found: Error: Can't resolve 'plugins/reporting/lib/job_completion_notifications' in '/usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export'\n"}

 FATAL  Error: Optimizations failure.
   8001 modules
    
    ERROR in /usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export/index.js
    Module not found: Error: Can't resolve 'plugins/reporting/lib/job_completion_notifications' in '/usr/share/kibana/node_modules/x-pack/plugins/canvas/public/components/workpad_export'

[elasticmachine]

Pinging @elastic/kibana-canvas

[akhilvatts]

+1 for 6.5.0
stuck for hours.
Please provide resolution.
Error:
{"type":"log","@timestamp":"2018-11-16T12:27:30Z","tags":["info","optimize"],"pid":17177,"message":"Optimizing and caching bundles for ml, stateSessionStorageRedirect, status_page, timelion, graph, monitoring, space_selector, login, logout, dashboardViewer, apm, canvas, infra and kibana. This may take a few minutes"}

[w33ble]

@akhilvatts optimize time isn't really a canvas problem, and isn't really related to this issue. #19678 is what you want, and it seems you already found it.

[pk241011]

Referencing the discussion thread I created instead of creating a bug. This looks similar to the issue I am facing.
Kibana not starting. Stuck at “Optimizing and caching bundles….”