[SPARK-50979][CONNECT] Remove .expr/.typedExpr implicits

[hvanhovell]

What changes were proposed in this pull request?

This PR removed the .expr/.typedExpr Column conversion implicits from the Connect client.

Why are the changes needed?

Code clean-up.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Existing tests.

Was this patch authored or co-authored using generative AI tooling?

No.

[dongjoon-hyun]

+1, this looks like a safe clean-up. BTW, are these all of them, @hvanhovell ?

[vrozov]

Based on failed test, there may be user facing change as plan changes.

[dongjoon-hyun]

Oh, ya. The plan becomes different.

[info] - hint *** FAILED *** (11 milliseconds)
[info]   Expected and actual plans do not match:
[info]   
[info]   === Expected Plan (with excess fields trimmed) ===
[info]   common {
[info]     plan_id: 1
[info]   }
[info]   hint {
[info]     input {
[info]       common {
[info]         plan_id: 0
[info]       }
[info]       local_relation {
[info]         schema: "struct<id:bigint,a:int,b:double>"
[info]       }
[info]     }
[info]     name: "coalesce"
[info]     parameters {
[info]       literal {
[info]         integer: 100
[info]       }
[info]       common {
[info]         origin {
[info]           jvm_origin {
[info]             stack_trace {
[info]               class_loader_name: "app"
[info]               declaring_class: "org.apache.spark.sql.connect.Dataset"
[info]               method_name: "~~trimmed~anonfun~~"
[info]               file_name: "Dataset.scala"
[info]             }
[info]             stack_trace {
[info]               class_loader_name: "app"
[info]               declaring_class: "org.apache.spark.sql.connect.SparkSession"
[info]               method_name: "newDataset"
[info]               file_name: "SparkSession.scala"
[info]             }
[info]           }
[info]         }
[info]       }
[info]     }
[info]   }
[info]   
[info]   
[info]   === Actual Plan (with excess fields trimmed) ===
[info]   common {
[info]     plan_id: 1
[info]   }
[info]   hint {
[info]     input {
[info]       common {
[info]         plan_id: 0
[info]       }
[info]       local_relation {
[info]         schema: "struct<id:bigint,a:int,b:double>"
[info]       }
[info]     }
[info]     name: "coalesce"
[info]     parameters {
[info]       literal {
[info]         integer: 100
[info]       }
[info]       common {
[info]         origin {
[info]           jvm_origin {
[info]             stack_trace {
[info]               class_loader_name: "app"
[info]               declaring_class: "org.apache.spark.sql.functions$"
[info]               method_name: "lit"
[info]               file_name: "functions.scala"
[info]             }
[info]             stack_trace {
[info]               class_loader_name: "app"
[info]               declaring_class: "org.apache.spark.sql.connect.ColumnNodeToProtoConverter$"
[info]               method_name: "toLiteral"
[info]               file_name: "columnNodeSupport.scala"
[info]             }
[info]           }
[info]         }
[info]       }
[info]     }
[info]   } (PlanGenerationTestSuite.scala:160)