Fixing blank thoughts in verbose for "_Exception" Action

[svdeepak99]

Fixed the issue of blank Thoughts being printed in verbose when handle_parsing_errors=True, as below:

Before Fix:

Observation: There are 38175 accounts available in the dataframe.
Thought:
Observation: Invalid or incomplete response
Thought:
Observation: Invalid or incomplete response
Thought:

After Fix:

Observation: There are 38175 accounts available in the dataframe.
Thought:AI: {
    "action": "Final Answer",
    "action_input": "There are 38175 accounts available in the dataframe."
}
Observation: Invalid Action or Action Input format
Thought:AI: {
    "action": "Final Answer",
    "action_input": "The number of available accounts is 38175."
}
Observation: Invalid Action or Action Input format

@vowelparrot currently I have set the colour of thought to green (same as the colour when handle_parsing_errors=False). If you want to change the colour of this "_Exception" case to red or something else (when handle_parsing_errors=True), feel free to change it in line 789.