Recursive mappings not working on two letter inputs with the same initial

[Affonso-Gui]

Describe the bug
Recursive mappings don't work for some two letter inputs.

To Reproduce
Add the following mappings:

map gs V
map ga gs

Expected behavior
When pressing ga, the line-wise visual selection mode should start, but nothing happens.
(ga -> gs -> V).

Confirmed that vim 9.0 works as expected.

Environment:

First discovered the bug in the following environment, but also confirmed it on a clean source build in the VimApp and developer VS2022 instance.

• Visual Studio version: 2019
• VsVim version: 2.8.0.0
• Programming Language: C++
• Check(Type 'x') any that are installed:
  • ReSharper
  • Visual Assist

Additional context
The problem seems to be caused by trying to comply with the following vim specification (:help recursive_mapping)

If the {rhs} starts with {lhs}, the first character is not mapped again (this is Vi compatible). 
For example:
    :map ab abcd
will execute the "a" command and insert "bcd" in the text.  The "ab" in the {rhs} will not be mapped again.

It seems that we are currently checking for {rhs} starts with the same letter than {lhs}, rather than {rhs} starts with {lhs}, which is causing trouble when we have two letters in lhs.
https://github.com/VsVim/VsVim/blob/master/Src/VimCore/KeyMap.fs#L77-L85

I am available for drafting a PR and some tests, if that would be welcome.