Unnecessary reallocation of DirAC metadata buffers in SBA bit rate switching
### Basic info
- Commit SHA: main
- Platform: all
### Bug description
The fix for #391 introduces a flag `dirac_param_estim_old` which is set after resetting `dirac_param_estim` in `ivas_dirac_config` meaning that reallocation of the DirAC MD buffers is triggered on a bit rate switch even if decoder parameter estimation is on for both the previous and current bit rate. Will be handled in a cumulative fix for this issue and issues #393, #459, #460.
### Ways to reproduce
(Clear steps or refer to a failing automated test, e.g. with a pipeline link)
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issue