Show dependencies of upgrading mods in change set

[HebaruSan]

Problem

1. Install xScience 5.26
2. Upgrade to the latest version
3. The change set shows just the upgrade:
   
4. However, the install screen shows that new dependencies will be installed:
   
   The user should be told about this in the change set screen.

Cause

The change set screen has always only looked for dependencies for modules being installed, not upgraded.

I think the expectation was that all of the complicated stuff would happen for installs, while upgrades would be simple replacements of one version of a module with a newer version, even though the underlying relationship logic in Core can handle more complicated scenarios.

Changes

Now upgrades will be treated more like installs, in that any new dependencies they introduce will be displayed:

To make this work, we also need to fix ComputeChangeSetFromModList to use the upgraded version in calculating the change set. It was using the old version; luckily this only affects the change set screen and not the actual install, which is handled in Core.

Fixes #3559.

[DasSkelett]

This comment needs updating,

CKAN/GUI/Controls/Changeset.cs

Lines 23 to 25 in d09ac3a

	// We're going to split our change-set into two parts: updated/removed mods,
	// and everything else (which right now is replacing and installing mods, but we may have
	// other types in the future).

"updated" is no longer part of the first group

Otherwise looks good to me

[HebaruSan]

Updated! Sometimes writing extra documentation can be a liability of sorts...

[DasSkelett]

Doesn't break more complex changeset scenarios, so that's a plus 😄