Add config param to customize single vs multi oncokb icons

[onursumer]

Related to #8710

Checks

• Runs on heroku
• Has tests or has a separate issue that describes the types of test that should be created. If no test is included it should explicitly be mentioned in the PR why there is no test.
• The commit log is comprehensible. It follows 7 rules of great commit messages. For most PRs a single commit should suffice, in some cases multiple topical commits can be useful. During review it is ok to see tiny commits (e.g. Fix reviewer comments), but right before the code gets merged to master or rc branch, any such commits should be squashed since they are useless to the other developers. Definitely avoid merge commits, use rebase instead.
• Is this PR adding logic based on one or more clinical attributes? If yes, please make sure validation for this attribute is also present in the data validation / data loading layers (in backend repo) and documented in File-Formats Clinical data section!

[inodb]

i think it's better to comment out this one. The default of true should be done in code rather than in the properties file. Issue is that when someone upgrades their cbioportal version they wouldn't have this property set in their existing properties file

[inodb]

maybe merge_icons_by_default? If we ever would want to give the option to not split the icons at all thru config then this is more explicit

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

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[inodb]

Thanks!