time: drop trailing space when not showing seconds at end

Seconds are not displayed when the value is smaller than 0.1s and
they are not at the start of the display output, e.g. `1h 2m`.
Drop the additional whitespace currently appended for this edge case.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>

proxmox-time/src/time_span.rs

@@ -170,11 +170,11 @@ impl std::fmt::Display for TimeSpan {
                 do_write(self.minutes, "min")?;
             }
         }
-        if !first {
-            write!(f, " ")?;
-        }
         let seconds = self.seconds as f64 + (self.msec as f64 / 1000.0);
         if seconds >= 0.1 {
+            if !first {
+                write!(f, " ")?;
+            }
             if seconds >= 1.0 || !first {
                 write!(f, "{:.0}s", seconds)?;
             } else {