Fix module naming typo in `multi-module` and `multi-module-not-on-root-with-correct-config` tests.

[Daniel-Khodabakhsh]

The module names were mixed up in a few places in src/sbt-test/sbt-sonar/:

• multi-module: Removed explicit name assignment because it matches the module val name, which SBT will automatically assign as the name as per the documentation.
• multi-module-not-on-root-with-correct-config: Fixed the names used for the modules.

[Daniel-Khodabakhsh]

Hey @mwz, I noticed you committed a fix for the third multi-module project in this same folder here: https://github.com/sonar-scala/sbt-sonar/commit/f1072403e2c04452dd157c097c58170fd0ae22a9 This PR I have open right now fixes the other two multi-module projects in a similar way.