More descriptive error message for pushing to empty analysis model

#### Description:

When attempting to push elements without bars, the error message shown did not describe the error in detail. The error message was "Invalid analysis/loadcase".

#### Steps to reproduce:

Push elements without an analysis in Lusas

#### Expected behaviour:

A message describing the issue, such as "The user needs to create at least one Analysis as per the default model in Lusas."

#### Test file(s):

https://burohappold.sharepoint.com/:u:/r/sites/BHoM/Installers/Scripts/Burohappold_BHoM_v7.3/Structures%20-%20Create%20-%20Read%20-%20Update%20-%20Elements/BuroHappold_BHoM_v7.1.beta_Create%20-%20read%20-%20elements%20-%20bridges.gh?csf=1&web=1&e=8iM0yX

Start by reproducing the issue with the linked Structures - Create - Read - Update - Elements test file, pushing elements without an analysis in Lusas. Find where the "Invalid analysis/loadcase" message is produced and make the failure explain that at least one Analysis is required; confirm the updated message during the same reproduction.

Written by the indexing model from the issue text.