Can't aggregate date values with NaT in pandas columns

Question

I have a dataframe like this:

df = pd.DataFrame({"CLASS":["A","A","B"],
                   "ACTION 1":[np.nan, "01-01-2022", np.nan],
                   "ACTION 2":["01-04-2022", np.nan, "01-12-2022"]})

df["ACTION 1"] = pd.to_datetime(df["ACTION 1"])
df["ACTION 2"] = pd.to_datetime(df["ACTION 2"])

df
Out[10]: 
  CLASS   ACTION 1   ACTION 2
0     A        NaT 2022-01-04
1     A 2022-01-01        NaT
2     B        NaT 2022-01-12

I would like to concat/aggregate these rows by the same value in column CLASS as filter, with the dates replacing the NaT values like this:

  CLASS   ACTION 1   ACTION 2
0     A 2022-01-01 2022-01-04
1     B        NaT 2022-01-12

Anyone could help me?