Welcome to the community!
Certainly, this can be done.
It does require you to add an output parameter to your flow, like below.

What I have done here is I have added a parallel branch which will trigger if the previous step (Send an HTTP request... in my case) fails. However, for trying this out, you could start with only one branch and have the success = True statement.
IMPORTANT!
As soon as you change input and/or output to a Power Automate flow, which you already have added to a PowerApps, needs to be removed and added anew within your PowerApps applications.
Now, in PowerApps for your OnSelect event property, you can have something like the below expression:
If(
'Power Automate Flow to Run'.Run().success = "True",
Notify(
"Flow has run successfully.",
NotificationType.Success,
2000
),
Notify(
"Flow run has failed.",
NotificationType.Error,
5000
)
);
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