[projmgr] Relax project provided `connections` validation

[grasci-arm]

Address https://github.com/Open-CMSIS-Pack/devtools/issues/1529:

• Project is valid even when no connections from the project are being consumed

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 63.36%. Comparing base (85a03c6) to head (5753c96).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1531 +/- ## ========================================== - Coverage 63.36% 63.36% -0.01% ========================================== Files 162 162 Lines 30911 30912 +1 Branches 18944 18945 +1 ========================================== - Hits 19587 19586 -1 - Misses 7552 7555 +3 + Partials 3772 3771 -1 ``` | [Flag](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack) | Coverage Δ | | |---|---|---| | [projmgr-cov](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack) | `80.44% <100.00%> (-0.02%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack) | Coverage Δ | | |---|---|---| | [tools/projmgr/include/ProjMgrUtils.h](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531?src=pr&el=tree&filepath=tools%2Fprojmgr%2Finclude%2FProjMgrUtils.h&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack#diff-dG9vbHMvcHJvam1nci9pbmNsdWRlL1Byb2pNZ3JVdGlscy5o) | `87.50% <ø> (ø)` | | | [tools/projmgr/src/ProjMgrWorker.cpp](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531?src=pr&el=tree&filepath=tools%2Fprojmgr%2Fsrc%2FProjMgrWorker.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack#diff-dG9vbHMvcHJvam1nci9zcmMvUHJvak1ncldvcmtlci5jcHA=) | `86.67% <100.00%> (-0.07%)` | :arrow_down: | | [tools/projmgr/test/src/ProjMgrUnitTests.cpp](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531?src=pr&el=tree&filepath=tools%2Fprojmgr%2Ftest%2Fsrc%2FProjMgrUnitTests.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack#diff-dG9vbHMvcHJvam1nci90ZXN0L3NyYy9Qcm9qTWdyVW5pdFRlc3RzLmNwcA==) | `79.60% <ø> (ø)` | | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/Open-CMSIS-Pack/devtools/pull/1531/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Open-CMSIS-Pack)

[github-actions[bot]]

Test Results

    3 files     18 suites   6m 28s :stopwatch:   334 tests   334 :white_check_mark: 0 :zzz: 0 :x: 1 002 runs  1 002 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 5753c96e.