Upgrade yarn + typescript packages on Jenkins to address missing whitespace error

[CloudNiner]

Any line in a jsdoc comment containing @param like:

* @param indicatorName - Name of indicator, used for SVG selector

such as the ones in image-export.service.ts throws the error:

ERROR: /opt/app/src/app/services/image-export.service.ts[23, 15]: missing whitespace

but only in the Jenkins environment, which has an outdated version (0.24.4) of yarn.

In #324 we temporarily addressed this by disabling the tslint whitespace.check-separator rule. A more thorough fix would be to ensure that yarn + typescript + tslint +tsutils are all up to date and then re-add the check-whitespace rule.

See palantir/tslint#3251 for a full writeup of the original problem.

[CloudNiner]

In addition, @maurizi left this comment in slack:

builds aren't (yet) isolated from each other

which may be appropriate to address as well to avoid transient errors when builds change the installed package versions.

[maurizi]

builds aren't (yet) isolated from each other

I think the changes in #321 are meant to address this issue.