prompt_pass not working on windows when using CTRL+V to paste the password string to console

[atbagga]

Issue: prompt_pass is not working on windows with CTRL+V being used to enter the input

Repro:

### CODE PART 1 ###
# ** getpass_fails.py ** #

from knack.prompting import prompt_pass
password = prompt_pass(msg="Password: ")
print(password)

Steps to repro:

1. Copy a text to clipboard using CTRL+C e.g. "mypassword"
2. On CMD or powershell prompt python getpass_fails.py
3. On Password: prompt use CTRL+V to paste the copied text.

Actual Behavior:

Expected Behavior:

WORKAROUND: The issue in only in using Ctrl+V to paste. If we use console menu or right click to paste it works correctly.

[atbagga]

This is heavily used in Azure CLI and its extensions. Azure-devops extension uses this function to accept Personal Access Token for login. Since it is an arbitrary long string people are used to using Ctrl+v for it.

Although the issue is in getpass library code.. Not sure where to follow up on it.
Confirmed by reproducing the above behavior using these code snippets:

### CODE PART 2 - Issue using getpass ###
# import getpass
# password = getpass.getpass(prompt="Password: ")
# print(password)

### CODE PART 3 - Issue using  win_getpass function from the getpass module ###
# import msvcrt
# def win_getpass(prompt='Password: ', stream=None):
#     """Prompt for password with echo off, using Windows getch()."""
#     for c in prompt:
#         msvcrt.putwch(c)
#     pw = ""
#     while 1:
#         c = msvcrt.getwch()
#         if c == '\r' or c == '\n':
#             break
#         if c == '\003':
#             raise KeyboardInterrupt
#         if c == '\b':
#             pw = pw[:-1]
#         else:
#             pw = pw + c
#     msvcrt.putwch('\r')
#     msvcrt.putwch('\n')
#     return pw


# password = win_getpass(prompt="Password: ")
# print(password)

@tjprescott

[atbagga]

Also created an issue - https://bugs.python.org/issue37426 for this.