chore(fgs): upgrade the parameters description and import validation

[wuzhuanhong]

What this PR does / why we need it:

1. Add note for app_agency and concurrency_num parameters of the huaweicloud_fgs_function resource.
2. Remove package and xrole parameters from ignore_changes.
3. Adjust scceptance test.

Which issue this PR fixes:
(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)
fixes #xxx

Special notes for your reviewer:

Release note:

1. add note for app_agency and concurrency_num parameters of the huaweicloud_fgs_function resource.
2. remove package and xrole parameters from ignore_changes.
3. adjust scceptance test.

PR Checklist

• Tests added/passed.

 ./scripts/coverage.sh -o fgs -f TestAccFgsV2Function_
Prepare to calculate the coverage the following command:
TF_ACC=1 go test "./huaweicloud/services/acceptance/fgs" -v -coverprofile="./huaweicloud/services/acceptance/fgs/fgs_coverage.cov" -coverpkg="./huaweicloud/services/fgs" -run TestAccFgsV2Function_ -timeout 360m -parallel 10
=== RUN   TestAccFgsV2Function_basic
=== PAUSE TestAccFgsV2Function_basic
=== RUN   TestAccFgsV2Function_withEpsId
=== PAUSE TestAccFgsV2Function_withEpsId
=== RUN   TestAccFgsV2Function_text
=== PAUSE TestAccFgsV2Function_text
=== RUN   TestAccFgsV2Function_createByImage
=== PAUSE TestAccFgsV2Function_createByImage
=== RUN   TestAccFgsV2Function_logConfig
=== PAUSE TestAccFgsV2Function_logConfig
=== RUN   TestAccFgsV2Function_strategy
=== PAUSE TestAccFgsV2Function_strategy
=== RUN   TestAccFgsV2Function_versions
=== PAUSE TestAccFgsV2Function_versions
=== RUN   TestAccFgsV2Function_domain
=== PAUSE TestAccFgsV2Function_domain
=== RUN   TestAccFgsV2Function_reservedInstance_version
=== PAUSE TestAccFgsV2Function_reservedInstance_version
=== RUN   TestAccFgsV2Function_reservedInstance_alias
=== PAUSE TestAccFgsV2Function_reservedInstance_alias
=== RUN   TestAccFgsV2Function_gpuMemory
=== PAUSE TestAccFgsV2Function_gpuMemory
=== CONT  TestAccFgsV2Function_basic
=== CONT  TestAccFgsV2Function_versions
=== CONT  TestAccFgsV2Function_createByImage
=== CONT  TestAccFgsV2Function_text
=== CONT  TestAccFgsV2Function_withEpsId
=== CONT  TestAccFgsV2Function_strategy
=== CONT  TestAccFgsV2Function_gpuMemory
=== CONT  TestAccFgsV2Function_reservedInstance_version
=== CONT  TestAccFgsV2Function_domain
=== CONT  TestAccFgsV2Function_logConfig
=== CONT  TestAccFgsV2Function_gpuMemory
    acceptance.go:804: HW_FGS_GPU_TYPE must be set for FGS acceptance tests
--- SKIP: TestAccFgsV2Function_gpuMemory (0.09s)
=== CONT  TestAccFgsV2Function_reservedInstance_alias
--- PASS: TestAccFgsV2Function_text (175.06s)
--- PASS: TestAccFgsV2Function_withEpsId (185.15s)
--- PASS: TestAccFgsV2Function_reservedInstance_alias (434.71s)
--- PASS: TestAccFgsV2Function_reservedInstance_version (444.76s)
--- PASS: TestAccFgsV2Function_versions (641.51s)
--- PASS: TestAccFgsV2Function_strategy (1103.71s)
--- PASS: TestAccFgsV2Function_createByImage (1265.35s)
--- PASS: TestAccFgsV2Function_logConfig (1306.55s)
--- PASS: TestAccFgsV2Function_domain (1342.61s)
--- PASS: TestAccFgsV2Function_basic (1451.25s)
PASS
coverage: 29.5% of statements in ./huaweicloud/services/fgs
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/fgs       1451.341s       coverage: 29.5% of statements in ./huaweicloud/services/fgs```

* [x] Documentation updated.
* [ ] Schema updated.
* [ ] CheckDeleted.

  - **a. During query operation (Read Context)**
    aa. Resource not found
    \>>>>>> Paste the screenshot here <<<<<<

    <!-- If the resource depends the parent resource(s), please provide the related check result(s) of the CheckDeleted validation.
    ab. Related resources (parent resources) not found
    \>>>>>> Paste the screenshot here <<<<<<
    -->
  - **b. During delete/disassociate/unbind operation (Delete Context)**
    ba. Resource not found
    \>>>>>> Paste the screenshot here <<<<<<

    <!-- If the resource depends the parent resource(s), please provide the related check result(s) of the CheckDeleted validation.
    bb. Related resources (parent resources) not found
    \>>>>>> Paste the screenshot here <<<<<<
    -->

[Lance52259]

/approve
/lgtm

[github-ci-robot]

This PR has been approved by: @Lance52259

/approve
/lgtm