…sonic-net#194)

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### Description of PR
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Summary:
Fix method collect_dut_lossless_prio.
The pfc_enable parameter can be empty.
Without this change we can get error:
```
> result = [int(x) for x in port_qos_map[intf]['pfc_enable'].split(',')]
E ValueError: invalid literal for int() with base 10: ''
```

PRs with related changes:
sonic-net/sonic-buildimage#22252
sonic-net/sonic-buildimage#22067

### Type of change

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- [x] Bug fix
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- [ ] Bug fix
- [ ] Testbed and Framework(new/improvement)
- [ ] New Test case
- [ ] Skipped for non-supported platforms
- [x] Test case improvement

### Back port request
- [ ] 202012
- [ ] 202205
- [ ] 202305
- [ ] 202311
- [ ] 202405
- [x] 202411

### Approach
#### What is the motivation for this PR?
stable test_pretest.py

#### How did you do it?
Used method `get`

#### How did you verify/test it?
Test passed after changes

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* 664f0e2 2021-07-14 | [xrcvd]: Removed undefined symbol 'sfp_status_helper' (sonic-net#204) (HEAD, origin/202012) [Prince George]
* 1b2d016 2021-06-16 | [CI] sonic-config-engine now depends on SONiC YANG packages (sonic-net#194) [Joe LeVeque]
* 1cf5996 2021-07-14 | Introduce mgmtinit delay after transceiver module insertion (sonic-net#201) [Prince George]

Signed-off-by: Guohan Lu <lguohan@gmail.com>

… submodule head (sonic-net#12494)

utilities:
* 02eb899e 2022-07-12 | [config/load_mgmt_config] Support load IPv6 mgmt IP (sonic-net#2206) (sonic-net#2246) (sonic-net#2256) (HEAD -> 201811, github/201811) [Jing Kan]

platform-daemon:
* fc288cc 2022-05-05 | Mem leak caused by Xcvrd in Send-Q of REDIS-DB socket connection (sonic-net#260) (HEAD -> 201811, github/201811) [Prince George]

platform-common:
* edb062b 2022-02-09 | [sonic_sfp] Interpret sff 'int' element =0 as valid value (sonic-net#261) (HEAD -> 201811, github/201811) [Prince George]

kernel:
* 9d2d1a1 2022-02-11 | [201811] Increase log_buf_len size to 1M (HEAD -> 201811, github/201811) [Sujin Kang]
* b34a213 2022-02-10 | [201811] Increase log_buf_len size to 1M [Samuel Angebault]
* c4684cb 2022-02-11 | [201811] Apply kernel patches to fix emmc unreliability [Sujin Kang]
* df68771 2022-02-03 | [201811] Apply kernel patches to fix emmc unreliability [Samuel Angebault]
* f21cb06 2021-03-26 | [ci]: remove 201811 suffix (sonic-net#204) [lguohan]
* 5439b2a 2021-02-08 | [dni_dps460] Add attributes to retrieve PMBus status command codes (sonic-net#194) [Arun Saravanan Balachandran]

Signed-off-by: Ying Xie <ying.xie@microsoft.com>

Signed-off-by: Ying Xie <ying.xie@microsoft.com>