bugfix: fix xidInterceptorType is null

[cmonkey]

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes #1908

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[slievrly]

LGTM

[codecov-io]

Codecov Report

Merging #1909 into develop will increase coverage by <.01%.
The diff coverage is 0%.

@@              Coverage Diff              @@
##             develop    #1909      +/-   ##
=============================================
+ Coverage      55.41%   55.42%   +<.01%     
- Complexity      2406     2407       +1     
=============================================
  Files            428      428              
  Lines          14351    14353       +2     
  Branches        1699     1700       +1     
=============================================
+ Hits            7953     7955       +2     
- Misses          5682     5683       +1     
+ Partials         716      715       -1

Impacted Files	Coverage Δ	Complexity Δ
...c/main/java/io/seata/core/context/RootContext.java	36.17% <0%> (-1.61%)	9 <0> (ø)
...server/store/file/FileTransactionStoreManager.java	58.54% <0%> (+0.63%)	30% <0%> (+1%)	⬆️

[zhongfuhua]

public static void bindInterceptorType(String xidType) {
        if(StringUtils.isNotBlank(xidType)){
            String[] xidTypes = xidType.split("_");
            if(xidTypes.length == 2){
                bindInterceptorType(xidTypes[0], BranchType.valueOf(xidTypes[1]));
            }
        }
    }

[jsbxyyx]

LGTM