Import externally generated files on Muon ALC interface

[robertapplin]

Report to: Adam Berlie

Description of work

This PR makes it possible to import a workspace from the ADS into the Muon ALC interface if it has 1 histogram. The data can be loaded into Mantid from a *.dat or *.txt file for example, and then imported into the Muon ALC interface as long as its a matrix workspace.

Fixes #38353

To test:

1. Load the following data
   QLCR150K.zip

2. Open Muon->ALC interface

3. Click Import results... in the bottom left

4. Enter the name of the workspace and click Okay

5. The plot should be populated with the data

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[robertapplin]

I will send this package to Adam Berlie for testing:
https://builds.mantidproject.org/job/build_packages_from_branch/947/

[github-actions]

👋 Hi, @robertapplin,

Conflicts have been detected against the base branch. Please rebase your branch against the base branch.

[robertapplin]

Adam is happy with the changes:

Your new update to the ALC import worked well! I could load in my .dat file and analyse it 🙂