feat: support custom IDP in logon

[lechnerc77]

Purpose

• Support custom IDP parameter for logon with BTP CLI

Does the PR solve an issue

[X] Yes - #545 
[ ] No

Does this introduce a breaking change?

[ ] Yes
[X] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[X] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

Logon with custom IDP

What to Check

Verify that the following are valid

• Log on succeeds

Other Information

n/a

[rui1610]

lgtm