banktags: improve bank scrollbar updates

With tag tab tab or "Remove tab separators", the scrollbar height needs to be
adjusted to account for either many tag tabs (which requires scrolling to see)
or the hiding of the tab separators. This is because we artifically filter the
bank results without keeping the bank in searching mode, causing the vanilla
code which usually computes the scroll height to be incorrect.

The existing code does this by manually invoking [proc,update_scrollbar] later
with the recomputed scroll height. Now that invokeLater runs next tick and not
next frame, this leaves several frames with the scrollbar the incorrect size.

The desired scroll height is passed to [proc,bankmain_finishbuilding] in
argument int12, so instead we recompute the scroll height and overwrite the
script argument prior to execution.

runelite-client/src/main/scripts/BankSearchFilter.rs2asm

@@ -1,4 +1,4 @@
-.id                 279
+.id                 279 ; [proc,bankmain_filteritem]
 .int_stack_count    1
 .string_stack_count 0
 .int_var_count      2 ; +1 for storage of search filter result

runelite-client/src/main/scripts/BankSearchLayout.rs2asm

@@ -1,4 +1,4 @@
-.id                 277
+.id                 277 ; [proc,bankmain_build]
 .int_stack_count    17
 .string_stack_count 0
 .int_var_count      36
@@ -842,7 +842,7 @@ LABEL729:
    iload                  14
    iload                  15
    iload                  16
-   invoke                 505
+   invoke                 505 ; [proc,bankmain_finishbuilding]
    return                
 LABEL750:
    invoke                 514